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Orphanet Journal of Rare Diseases

Springer Science and Business Media LLC

Preprints posted in the last 30 days, ranked by how well they match Orphanet Journal of Rare Diseases's content profile, based on 18 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

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Understanding the Patient Journey, Current Treatment Approaches and Emerging Therapeutic Opportunities in CLN2 Batten Disease

Whiteman, I. T.; Villa, K. L.; Spector, C. M.; Cha, J.-H. J.; Fenton Parker, A.; Ahrens-Nicklas, R.; Schulz, A.; Yohrling, G. J.

2026-06-02 neurology 10.64898/2026.05.31.26354557 medRxiv
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Background CLN2 disease, Neuronal Ceroid Lipofuscinosis (NCL) type 2, is a rare, genetic neurodegenerative condition predominantly affecting children. CLN2 disease is characterized by seizures, language and motor decline, vision loss, and premature death. Currently, the only regulatory-approved therapy is the enzyme replacement therapy (ERT) Cerliponase alfa, administered fortnightly via intracerebroventricular infusion as a lifelong treatment. While ERT has been shown to slow motor and language decline, it is not curative and does not fully address disease progression, including retinal degeneration. To better understand the lived experience of affected families, and perspectives on current and emerging treatments, we conducted a community survey of parents and caregivers of individuals with CLN2 disease. Methods A 25-question anonymous, voluntary survey was distributed through the BDSRA Foundation and international partner patient advocacy organisations via email and social media. Eligible participants included current and bereaved parents or primary caregivers of individuals with CLN2 disease, regardless of treatment history. The survey explored treatment experiences, unmet needs, and knowledge of and attitudes toward emerging therapeutic approaches, particularly gene-based therapies. Results Ninety-eight respondents from 19 countries completed the survey. Fifty-seven respondents reported current or prior use of ERT, with 94.7% (n=54/57) actively receiving treatment at the time of survey. ERT was perceived to provide greatest benefit for motor function and seizure control; however, respondents reported substantial treatment burden (mean burden score 4.8/7, n=66). Despite treatment availability, 94.9% of respondents (n=75/79) indicated a need for alternative therapeutic options and 94.8% (73/77) expressed interest in learning more about gene therapy. Overall, 72.4% (n=55/76) reported they were likely or very likely to consider participation in an investigational gene therapy trial. Key factors influencing decision-making included potential safety risks (57.9%, n=44/76), preclinical safety and efficacy evidence (54.0%, n=41/76), and whether ERT discontinuation would be required to participate (54.0%, n=44/76). Conclusion While ERT has altered the treatment landscape for CLN2 disease, this survey highlights the ongoing disease burden and treatment challenges experienced by families. Findings demonstrate strong community interest in next-generation therapies that may reduce treatment burden and provide more comprehensive disease modification, including effects on both central nervous system (CNS) and ocular manifestations.

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Cortical Organoid Model of PPP2R5D Genetic Intellectual Disability Models Disease Severity Phenotype

Du, Y.; Singh, M.; Patil, M.; Villeagas, I.; Portillo, A.; Shang, K.; Ben-Shalom, R.; Halmai, J.; Fink, K.

2026-05-27 cell biology 10.64898/2026.05.26.728012 medRxiv
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Jordans Syndrome (JS) is a rare, neurodevelopmental disorder caused by de novo missense mutations in protein phosphatase 2 regulatory subunit Bdelta (PPP2R5D). JS is characterized by severe neurological impairments starting in early life. PPP2R5D encodes for B56{delta}, one of the regulatory subunits of protein phosphatase 2A (PP2A). PP2A is a heterotrimeric protein serine/threonine phosphatase that is highly expressed in the brain and the liver. Past studies have focused on PP2As role in liver and little is known about the holoenzymes behavior in neuronal cells. Although B56{delta} is known to play an important role in the substrate specificity of PP2A, the identification of validated downstream substrates in JS remains unclear. To better understand how the mutations affect neuronal cells, we developed cerebral cortical-like organoids from an engineered allele series of the most common JS mutations to characterize the physiological changes throughout different stages of neurodevelopment. Organoids were assessed for transcriptomic, protein, and electrophysiological changes utilizing bulk RNA sequencing, immunocytochemistry, Western Blot, and high-density MicroElectrode Array. The results identify differentially expressed genes and translated proteins, potential neuronal substrates, and significant electrophysiological signatures that suggest mutations in B56{delta} lead to variant-specific dysfunction of PP2A. Overexpression of PPP2R5D through AAV transduction of organoids rescued several phenotypes in the variants, suggesting different pathogenetic etiology underneath. Our findings successfully characterized cerebral cortical-like organoids in JS cell lines and demonstrated its potential as a model for studying neurodevelopmental disorder and for screening therapeutic approaches.

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Translation, cross-cultural adaptation, and psychometric evaluation of the colour blind quality of life scale into Vietnamese

Thuy, T. T.; Woi, P. J.; Hairol, M. I.; Vu, Q. A.

2026-05-20 health systems and quality improvement 10.64898/2026.05.15.26353359 medRxiv
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Background: The Colour Blind Quality of Life Scale (CBQoL) is a questionnaire developed to assess the quality of life of individuals with congenital colour vision deficiency (CVD). This study aimed to translate the English version of the CBQoL into Vietnamese and evaluate the validity and reliability of the Vietnamese version (CBQoL-VN). Methods: A forward-backward translation method was performed to produce the Vietnamese text. Content validity was assessed by six experts in vision care. Reliability testing involved 30 participants with congenital CVD, while discriminant validity was evaluated by comparing this group against 30 participants with normal colour vision. Results: Following expert consensus, two items were removed and one transportation-related item was added. The content validation index (CVI) values of 1.0 for relevance, clarity, and understandability indicated excellent content validity. Internal consistency was high, with a Cronbach's alpha of 0.95 for the full scale. Discriminant validity analysis showed that participants with congenital CVD scored significantly lower across all CBQoL-VN domains compared to those with normal colour vision. Conclusions: The modified CBQoL-VN is a valid and reliable instrument for assessing the quality of life of individuals with congenital CVD in the Vietnamese population.

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The Genetic Landscape and Epidemiological Characteristics of Inherited Retinal Diseases in the Chinese Population

Zeng, B.; Cui, Z.; Zhou, S.; Dai, W.

2026-05-29 ophthalmology 10.64898/2026.05.27.26354224 medRxiv
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Background: Inherited Retinal Diseases (IRDs) are a group of genetically heterogeneous blinding conditions. Major global genomic reference databases are disproportionately enriched for individuals of European ancestry. This underrepresentation creates a significant bias that impedes the accuracy of genetic diagnosis in the Chinese population. This study aims to address this limitation by constructing a comprehensive genetic landscape of IRDs using large-scale deep-sequencing data from a large Chinese cohort. Methods: The study leveraged variant data primarily from 10,588 individuals in the China Metabolic Analytics Project (ChinaMAP) and cross-referenced findings against multiple national and international databases. We systematically curated variants within a targeted panel of 291 IRD-associated genes. Variant pathogenicity was assessed using a comprehensive pipeline integrating InterVar-automated classification based on 2015 American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines, ClinVar evidence (review status [≥] 1 star), and manual literature curation. We delineated the mutational spectrum, identified population-enriched pathogenic/likely pathogenic (P/LP) variants, and analyzed the distribution characteristics of IRD-associated highly-mutated genes. Furthermore, we calculated the carrier frequencies (CF) and genetic prevalence (GP) of autosomal recessive(AR)-IRD genes in the Chinese population. Results: The study revealed a highly concentrated genetic landscape for AR-IRDs in the Chinese population, with ABCA4 and USH2A emerging as the primary drivers of the genetic burden. This finding aligns with previous Chinese cohorts but contrasts with global databases, where genes such as the X-linked RPGR are more prevalent. In contrast, autosomal dominant (AD)-IRDs exhibited high locus heterogeneity, with pathogenic variants dispersed across numerous genes (e.g., COL2A1 and MFN2). We identified a series of P/LP variants that were either high-frequency or significantly enriched in the Chinese population, such as CNGB1 (p.P530R) and specific recurrent alleles in ABCA4 and CYP4V2. The estimated cumulative CF for AR-IRDs was 1 in 5.60, and the theoretical total GP was 1 in 2,624.67, based on the ChinaMAP data. Conclusion: By integrating the ChinaMAP dataset with diverse genomic resources, this study provides a genetic landscape of IRDs in the Chinese population. Our analysis shows a concentrated mutational spectrum in AR-IRDs, contrasting with the pronounced heterogeneity in AD-IRDs. These findings, including population-specific pathogenic variants and refined prevalence estimates, provide a resource for precision diagnostics, genetic counseling, expanded carrier screening (ECS), and public health policy development in China.

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Normative modeling for quantitative brain MRI phenotyping and biomarker discovery for pediatric leukodystrophies

Karandikar, S.; Sevagamoorthy, A.; Zimmerman, D.; D'Aiello, R.; Dorfschmidt, L.; Cyr, K.; Jung, B.; Levitis, E.; Adang, L. A.; Arnold, K.; Bennett, M. L.; Charsar, B. A.; Dominguez Gonzalez, C. A.; Gavazzi, F.; Hong, P.; Orthmann-Murphy, J. L.; Pham, S. T.; Kelley, K.; Lerner, M.; Shults, J.; Thakur, N.; Vossough, A.; Waldman, A. T.; White, A.; Whitehead, M. T.; Emrick, L.; Fraser, J.; Van Haren, K.; Keller, S.; Fatemi, A.; Eichler, F.; Bonkowsky, J. L.; The Global Leukodystrophy Initiative Clinical Trials Network Workgroup, ; Seidlitz, J.; Alexander-Bloch, A. F.; Vanderver, A.

2026-05-25 neurology 10.64898/2026.05.22.26353512 medRxiv
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Importance: Leukodystrophies are a heterogeneous group of genetic disorders affecting the white matter of the brain, often presenting with overlapping clinical features but differing in neuroanatomical involvement. There is a critical need for quantitative tools to characterize disease burden and support diagnosis, severity stratification, and clinical trial readiness. Objective: To characterize shared and distinct neuroanatomical patterns across six genetically confirmed leukodystrophies using anatomical MRI-derived phenotypes benchmarked against brain growth charts, and to assess the utility of this methodological approach for identifying imaging biomarkers of disease severity. Design, Setting, and Participants: Cross-sectional neuroimaging study using retrospective clinical MRI data. Setting: Multicenter study incorporating data from the Global Leukodystrophy Initiative Clinical Trials Network (GLIA-CTN) and control data from the Childrens Hospital of Philadelphia. Participants: The study included 434 MRI scan sessions from 274 patients with genetically confirmed leukodystrophies (Pelizaeus-Merzbacher disease, Metachromatic leukodystrophy, Alexander disease, Aicardi-Goutieres syndrome, TUBB4A-related leukodystrophies, and POLR3-related leukodystrophy). Control MRI data (7628 scans from 7205 subjects) were drawn from the Scans with Limited Imaging Pathology cohort at the Children's Hospital of Philadelphia. Exposures: All MRI scans underwent automated segmentation using deep learning segmentation tools to derive global and regional brain volumes. Normative models of brain development ("brain growth charts") were generated for the control cohort using generalized additive models for location, scale, and shape. Centile scores were then calculated for leukodystrophy subjects to quantify deviations from typical development. Main Outcomes and Measures: Centile scores for global and regional brain volumes were compared across leukodystrophy subtypes to identify disease-specific neuroanatomical patterns and to evaluate their potential utility for severity stratification. Results: Distinct patterns of neuroanatomical deviation were observed across leukodystrophy subtypes. Certain leukodystrophies showed preferential involvement of specific cortical or subcortical regions, while others displayed more diffuse volume loss. Centile scores demonstrated potential for differentiating disease subtypes and stratifying individuals by severity. Preliminary longitudinal data suggest centile scores may also track progression over time. Conclusions and Relevance:This study demonstrates the feasibility and utility of MRI profiling of individuals with leukodystrophy using anatomical MRI-derived phenotypes benchmarked against brain growth charts. The approach enables data-driven, quantitative characterization of structural brain abnormalities, offering a scalable method for phenotyping, diagnosis, and future use in clinical trials.

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Nutritional status, clinical burden, and healthcare utilization among pediatric outpatients with congenital heart disease: A retrospective cross-sectional study from Indonesia

Amelia, P.; Sahertian, L. C. D.; Adriansyah, R.; Kannady, J.

2026-05-26 cardiovascular medicine 10.64898/2026.05.23.26353925 medRxiv
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Congenital heart disease contributes substantially to chronic morbidity, growth impairment, and repeated healthcare utilization among children. Evidence regarding nutritional burden and outpatient healthcare patterns among pediatric patients with congenital heart disease in Indonesia remains limited. This study aimed to evaluate clinical characteristics, nutritional status, healthcare utilization, and factors associated with malnutrition among pediatric outpatients with congenital heart disease at Adam Malik General Hospital, Indonesia. A retrospective observational study was conducted using medical records of pediatric outpatients treated between January and December 2024. Demographic characteristics, cardiac diagnoses, nutritional status, complications, and outpatient visit history were analyzed. Logistic regression analysis was performed to identify factors associated with malnutrition. A total of 606 pediatric outpatients were included. Non cyanotic congenital heart disease predominated the cohort, with ventricular septal defect representing the most common diagnosis followed by patent ductus arteriosus and atrial septal defect. Nearly half of all patients demonstrated underweight or severe underweight nutritional status, while pulmonary hypertension emerged as the most frequent complication. Younger pediatric age groups and higher cumulative clinical burden independently increased the odds of malnutrition. Children with congenital heart disease at this tertiary referral center carried a substantial nutritional and clinical burden. Early nutritional surveillance and integrated long term outpatient management may improve growth outcomes and reduce chronic disease burden in resource limited settings.

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The D4Z4caster DNA methylation signature identifies individuals at epigenetic risk for developing facioscapulohumeral muscular dystrophy (FSHD)

Jones, T. I.; Eriksen, B. Z.; Farooqi, M. N.; Gould, T.; Jones, P. L.; King, O. D.

2026-05-29 genetics 10.64898/2026.05.26.727947 medRxiv
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BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is caused by epigenetic dysregulation at the chromosome 4q35 D4Z4 repeat array under specific permissive genetic conditions. Due to the complexity, expense, and general inaccessibility of FSHD genetic testing, many individuals displaying characteristic muscle weakness are never genetically confirmed and at-risk relatives cannot get screened. We previously developed a targeted bisulfite sequencing (BSS) protocol using the Sanger method to determine DNA methylation levels at specific D4Z4 loci relevant to distinguishing forms of FSHD from non-FSHD that can be used with DNA isolated from saliva, thereby reducing cost and increasing accessibility compared to traditional D4Z4 deletion testing that uses DNA isolated from blood. MethodsHere, we adapt the D4Z4 BSS protocol to next-generation sequencing (NGS) to increase sequencing depth and further reduce cost, validate both sequencing technologies against several cohorts of genetically defined samples, and introduce the D4Z4caster software for computing DNA methylation signatures with diagnostic utility from raw sequencing data. ResultsBoth Sanger and NGS BSS methods using D4Z4caster were validated as providing high sensitivity and specificity, with geometric mean of sensitivity and specificity (G-mean) >95% and area-under-the ROC curve (AUC) of 0.99. The NGS method allows for higher throughput and increased read depth, while the Sanger method allows faster processing of individual samples. Importantly, the NGS method could identify FSHD1 cases that are likely mosaic and would otherwise be missed. ConclusionsD4Z4caster methylation signatures can accurately detect contracted FSHD1-permissive chromosome 4q35 alleles, hypomethylation of D4Z4 arrays indicative of FSHD2, and SNPs that are important for diagnostic use. This workflow is amenable to transitioning to clinical settings for an accurate, low-cost FSHD molecular diagnostic test that could be accessible worldwide. What is already known on this topicCurrently accepted genetic diagnostics for FSHD1 are complex and expensive and can mischaracterize certain complex genetic cases. These diagnostics all require high molecular weight genomic DNA typically freshly isolated from blood, highly specialized equipment, and additional testing for FSHD2, making FSHD diagnostics the most expensive among neuromuscular diseases and inaccessible to much of the world. However, the epigenetic status of the 4q35 and 10q26 D4Z4 repeat arrays, as determined by DNA methylation status using our bisulfite sequencing-based protocol, distinguishes genetically FSHD1, FSHD2, and non-FSHD samples. Additionally, since our protocol is PCR-based, it can utilize DNA isolated from multiple sources, including saliva and buccal swabs. What this study addsThis study validates the relevant DNA methylation signatures against several large cohorts of genetically-confirmed FSHD and non-FSHD samples and optimizes the DNA methylation data analysis for the greater accuracy required for diagnostic utility, including the exclusion of nonpathogenic chromosome 10q or 4A166 contractions. In addition, we introduce the D4Z4caster analysis software, which runs in a portable and scalable Docker container, and provides increased quantitative accuracy important for: 1) confirming likely clinical cases of FSHD that do not meet the currently accepted genetic definition of FSHD1 or FSHD2, 2) identifying FSHD1 somatic mosaicism, and 3) potential prognostic applications. How this study might affect research, practice or policyFSHD1 is genetically defined by a D4Z4 array at the 4q35 locus that is contracted to 1-10 repeat units. However, disease penetrance is influenced by repeat number, epigenetic modifications, and genetic background, causing a misalignment of current genetic diagnosis with clinical diagnosis. This study will improve the accuracy of epigenetic analysis for determining cases of genetic FSHD, help broaden the definition of genetic FSHD to more accurately correspond to clinical FSHD, and allow identification of those at risk for developing clinical FSHD in affected families and in large population studies now being performed and proposed. In addition, it will better inform how an individuals epigenetic status is interpreted for potential prognostic value. Overall, this methodology is: 1) significantly less expensive than current clinically-approved FSHD diagnostic technologies, 2) more accessible due to compatibility with DNA isolated from multiple sources including saliva, and 3) compatible with the current sequencing equipment and workflow for DNA isolation used in commercial clinical laboratories. Together, these advantages will help move the technology toward becoming an approved molecular diagnostic test for FSHD in the USA, Europe, and countries currently lacking clear access to testing.

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Rare neurological and neurodevelopmental variants in ALS link to onset, survival and family history

O'Donoghue, C.; Kacar, E.; Gomes, T.; Costello, E.; Pender, N.; Peelo, C.; Ryan, M.; Heverin, M.; Byrne, S.; Bede, P.; Hardiman, O.; McLaughlin, R. L.; Byrne, R. P.

2026-06-10 genetic and genomic medicine 10.64898/2026.06.09.26354977 medRxiv
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Background: Neurological, neuropsychiatric, and neurodevelopmental disorders cluster in ALS families, sharing a common genetic architecture with ALS. Pathogenic variants in genes associated with other neurological, neurodevelopmental, or neuropsychiatric disorders may also co-occur in ALS and modify phenotype. We have sought to determine the prevalence and clinical pattern of likely-pathogenic/pathogenic (LP/P) non-ALS neurological, neurodevelopmental, and neuropsychiatric variants, alone and in combination with ALS-gene variants, in two large ALS cohorts. Methods: Whole-genome sequencing (WGS) of 469 Irish and 774 Answer ALS people with ALS (pwALS) was analysed for ClinVar LP/P variants associated with other neurological (n = 15541), neurodevelopmental (n = 9761), and neuropsychiatric (n = 321) phenotypes. Inheritance patterns for associated genes (autosomal recessive/autosomal dominant) along with the associated phenotype were validated using OMIM. Standardised clinical data included family history, site and age of onset, El Escorial category, survival, motor decline, and cognitive and behavioural assessments. Known ALS-gene variants and C9orf72 repeat expansion status were included for each cohort. Results: Non-ALS neurological variants were identified in 47/469 (10.0%) Irish and 69/774 (8.9%) Answer ALS participants, most frequently in hereditary spastic paraplegia-associated genes (3.2% Irish; 2.8% Answer ALS). Irish neurological variant carriers showed higher frequency of respiratory onset (10.6% vs 1.2%, Fisher's exact p = 0.002, {Phi} = 0.20) and fewer premorbid behavioural symptoms (0.92 +/- 0.56 vs 3.08 +/- 0.97, Cohen's d = -0.40). Neurodevelopmental variants occurred in 12/469 (2.6%) Irish and 20/774 (2.6%) Answer ALS participants. In the Irish cohort, neurodevelopmental variant carriers had significantly shorter survival in Cox proportional hazards model (log-rank p = 0.005), corresponding to a more than two-fold increased hazard of death (HR = 2.25, 95% CI 1.26-4.00), and had significantly increased familial burden of neuropsychiatric disorders among first- and second-degree relatives (negative binomial IRR for carriers = 2.41, 95% CI: 1.12-5.18, p = 0.025). Across combined cohorts, 18 individuals (Irish n = 8; Answer ALS n = 10) carried [≥]2 LP/P variants spanning ALS and non-ALS genes. Conclusion: Rare LP/P variants in genes associated with other neurological and neurodevelopmental disorders occur in up to 12% of pwALS across two independent cohorts. Carriers show distinct phenotypes, shorter survival, and characteristic family history patterns. These findings suggest that extended pleiotropic and oligogenic architectures may contribute to ALS heterogeneity.

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Beyond Anatomical Severity: Determinants of Health-Related Quality of Life and Transition Readiness in Adolescents with Congenital Heart Disease

Abed, M.; Aiello, S.; Gill, N.; Alonso-Gonzalez, R.; Massarella, D.; Huang, R.; Morgan, C. T.

2026-05-22 cardiovascular medicine 10.64898/2026.05.20.26353746 medRxiv
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Background: Improved survival of adolescents with congenital heart disease has shifted the focus to examine health-related quality of life and address challenges in transition to adult care. We aim to describe how congenital heart disease complexity, gender, number of interventions, and Fontan circulation may affect the health-related quality of life and transition readiness of adolescents with congenital heart disease. Methods: We conducted a single-center cross-sectional study involving 536 patients aged 14 to 18 years old who attended a nurse-led, pediatric to adult care cardiac transition clinic, from 2020 to 2024. health-related quality of life was evaluated using the PedsQLTM 4.0 Generic Core Scales and the PedsQLTM 3.0 Cardiac Module. Patients were screened for anxiety and depression using the PHQ-9 and GAD-7. Transition readiness was assessed using the Transition-Q score. Results: The median age of patients was 16 years old and 44% self-identified as female. PedsQLTM 4.0 Generic had a median overall score of 77 (IQR 67?87), with no significant difference according to congenital heart disease severity. Female patients had significantly lower overall PedsQLTM 4.0 score (p=0.028) and lower physical and emotional functioning scores (p=0.005, p<0.001, respectively) when compared to males. Physical functioning scores were lower amongst patients with Fontan circulation compared to non-Fontan patients (p=0.003), although overall PedsQLTM 4.0 score and transition readiness scores were similar to those with complex biventricular congenital heart disease. Number of previous interventions were inversely associated with overall PedsQLTM 4.0 score (p=0.036). Moderate to severe symptoms of depression or anxiety were reported in 30% of screened patients and were associated with 2 significantly lower PedsQLTM 4.0 scores (p<0.001). Transition readiness was significantly lower in patients with moderate and complex compared to those with simple congenital heart disease (p<0.001). Transition readiness improved with repeat transition clinic visits (p=0.004) whereas PedsQLTM 4.0 score did not change significantly. Conclusion: In this large cohort of adolescents with congenital heart disease, health-related quality of life was lower than population norms. Female gender, higher interventional burden, and anxiety or depressive symptoms are associated with lower health-related quality of life scores rather than anatomical severity or Fontan physiology. Transition readiness was lower in complex disease; it has improved with a structured, nurse-led transition clinic, demonstrating modifiability. Consequently, adolescent congenital heart disease care requires a multidisciplinary approach including psychosocial screening, especially for high-risk groups, and structured transition planning to improve long-term outcomes.

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Care-seeking pathways and time to tertiary hospital presentation for stroke care in Ondo State, Nigeria

Ogunsemoyin, O.; Fayehun, O.

2026-06-08 health systems and quality improvement 10.64898/2026.06.04.26354906 medRxiv
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Introduction: Stroke care is time-sensitive, yet patients in low-resource settings may reach tertiary services only after passing through multiple formal and informal care options. This study examined documented care-seeking pathways and time to presentation among stroke cases recorded at the University of Medical Sciences Teaching Hospital (UNIMEDTH), Ondo State, Nigeria. Methods: A retrospective hospital record review was conducted using secondary data from the Stroke Registry, radiology department records, referral notes, and ambulance records at UNIMEDTH. The analysis included 371 stroke cases with documented time from symptom onset to UNIMEDTH presentation and reconstructable care pathways. First-contact routes were classified as hospital/biomedical, self/informal or traditional/faith-based care, and the number of documented steps defined pathway complexity before and including tertiary presentation. Frequencies and percentages described pathway patterns; median presentation times were compared using Mann-Whitney U and Kruskal-Wallis tests. Results: The median time to tertiary presentation was 24 hours (interquartile range [IQR] 9-72), and 317 patients (85.4%) presented after four hours. Only 30 patients (8.1%) presented directly to UNIMEDTH; 44 distinct care-pathway sequences were recorded. Hospital-facility first contact was documented for 81 patients (21.8%). It was associated with a median presentation time of 3 hours (IQR 2-6), compared with 48 hours (IQR 24-72) among patients whose initial contact was outside a hospital facility (U = 699.50, p < 0.001). The median time also differed across grouped first-contact categories and pathway complexity levels (both p < 0.001). Conclusion: Non-hospital or multi-step care-seeking pathways commonly preceded tertiary stroke presentations in this setting. The findings indicate that delayed tertiary arrival is partly embedded in the pathway followed after symptom onset. Interventions should combine public recognition of stroke warning signs with urgent referral linkages involving hospitals, patent medicine vendors, traditional and faith-based providers, and emergency transport systems.

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Calibrated high-throughput electrophysiology enables clinical interpretation of CACNA1G missense variants

Finol-Urdaneta, R. K.; Tan, C.-Y.; Maksemous, N.; Ma, J. G.; Lockhart, P.; Snell, P.; Malhotra, A.; Thompson, B. A.; Garg, G.; Goel, H.; Griffiths, L. R.; Adams, D. J.; Vandenberg, J. I.; Ng, C. A.

2026-05-18 neuroscience 10.64898/2026.05.10.724145 medRxiv
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ObjectiveAccurate classification of ion channel variants of uncertain significance (VUS) remains a persistent challenge in clinical genomics, limiting diagnostic resolution in neurological disorders. MethodsWe developed a calibrated electrophysiological framework to generate functional evidence for clinical interpretation of CACNA1G variants encoding the low-voltage-activated calcium channel Cav3.1. Functional metrics derived from automated patchclamp recordings were calibrated against benign/likely benign (B/LB) and pathogenic/likely pathogenic (P/LP) reference variants to enable conservative application of ACMG/AMP functional criteria within clinical variant interpretation workflows. ResultsCalibration using 25 B/LB and 16 P/LP CACNA1G variants showed that more than 80% of P/LP variants exhibited reduced current density (CD). Deactivation kinetics ({tau}Deact) provided complementary discriminatory information by identifying gating abnormalities in variants with preserved CD. Application of this dual-metric framework to five VUS identified in Australian patients revealed two variants (Cav3.1-R186Q and R1394Q) with abnormal functional profiles consistent with voltage-sensor perturbation, supporting reassessment as likely pathogenic under ACMG/AMP guidelines. The remaining VUS displayed functional properties overlapping the benign reference distribution. ConclusionThese findings establish a calibrated functional framework for generating electrophysiological evidence that supports clinical interpretation of CACNA1G missense variants under ACMG/AMP guidelines. When applied as external functional evidence, this approach improves resolution of CACNA1G-associated VUS while maintaining conservative standards for variant classification.

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Adaptable Stroke Education Improves Knowledge Across Diverse High School Settings

Namian, S.; DiBiase, R.; Elnazer, S. H.; Evers, C.; Fung, C.; Narula, R.; Rafferty, M.; Salahuddin, A.; Sardana, D. J.; Shea, J.; Sullivan, M.; Forman, R.

2026-05-18 neurology 10.64898/2026.05.14.26353185 medRxiv
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Background: High school students may be able to communicate health topics to peers and adults. Yet, few studies have evaluated the role of high school students in community health initiatives, making them an underutilized group for disseminating health information. We pilot tested stroke education across five high schools using varied delivery approaches as a preliminary step toward evaluating youth stroke education to improve community health. Methods: In April-May 2025, five high schools in Connecticut and New York participated in stroke education. The format was designed to fit the needs of each school and included an 8-session classroom curriculum (Derby, CT), after-school club meetings (New Haven, CT; Long Island, NY), and one large assembly (Bridgeport, CT). Developed by teachers and neurology providers, the curriculum covered stroke risk factors, symptoms, and emergency response. Students completed a 15-point assessment adapted from the validated Stroke Action Test before, immediately after, and 4-6 weeks post-intervention; data were collected between April and July 2025. Results: Of 112 students completing the pre-test, 99 (88%) completed the immediate post-test and 51 (46%) the delayed follow-up. Average scores rose from 47% pre-intervention to 75% post and 70% at 4-6 weeks. All schools scored <50% on pre-tests suggesting poor baseline stroke knowledge. Conclusion: This pilot suggests that stroke education can be delivered to high school students across varied settings and may support knowledge gains up to 6 weeks. Limitations included small sample sizes and missing follow-up data. If validated in larger studies, this adaptable, teacher-supported approach could offer a scalable public health strategy for improving community stroke preparedness.

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Three-Month Observational Data for the MPS IIIB Sentinel Subject Following AAV9 Mediated Gene Therapy

Ma, X.; Gu, R.; Ma, W.; Xu, Q.; Wang, R.; Wang, W.; Liang, M.; Liu, X.; Yang, X.; Zhuang, L.; Zhang, W.; Zeng, X.; Xu, J.; Xu, X.; Wu, Z.; Xia, Y.; Liu, Y.; Zhou, J.; Zhu, X.; Wang, H.; Dong, Z.; Yang, W.; Dai, Y.; Pan, X.; Li, X.; Wang, Y.; Dong, X.; Wu, X.; Feng, Z.

2026-06-09 neurology 10.64898/2026.06.01.26354386 medRxiv
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Background: Mucopolysaccharidosis type IIIB (MPS IIIB) is a devastating neurodegenerative lysosomal storage disorder caused by alpha-N-acetylglucosaminidase (NAGLU) deficiency. There is currently no approved therapy. We report the 3-month outcomes of a novel intracerebroventricular (ICV) gene therapy in a child with MPS IIIB. Methods: In an open-label, single-center, investigator-initiated trial (ChiCTR2600121466), a single dose of RDGT-101 (2.0E14; vg of an AAV9 vector encoding human NAGLU) was administered via ICV infusion. Primary outcomes were safety and tolerability. Secondary outcomes included serum NAGLU activity, urinary heparan sulfate (HS) excretion, and neurocognitive function. Exploratory analyses included hematological parameters. Results: The patient achieved serum NAGLU activity (17.06 nmol/mL/hour) approaching that of healthy controls (17.75 {+/-} 1.37 nmol/mL/hour) by Month 3, accompanied by a 58.4% reduction in urinary HS. Clinically, previously severe hand and toe contractures resolved, allowing for full extension. Neurocognitive improvements were observed, including clear articulation, logical conversation, and sustained eye contact. Hematological analyses revealed normalized red blood cell indices and improved iron utilization. No dose-limiting toxicities, serious adverse events, or clinically significant laboratory abnormalities were observed. Conclusions: A single ICV infusion of RDGT-101 was safe and well-tolerated in this patient with MPS IIIB. Early biochemical correction was accompanied by marked improvements in somatic, neurocognitive, and hematological parameters. These findings support further investigation of ICV AAV9 gene therapy for MPS IIIB.

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Natural History of Prenatally Identified Children with 48,XXYY Syndrome in Infancy and Early Childhood

Nocon, K.; Swenson, K.; Bothwell, S.; Howell, S.; Davis, S.; Ikomi, C.; Ross, J.; Tartaglia, N.

2026-06-04 pediatrics 10.64898/2026.06.04.26353909 medRxiv
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Background: 48,XXYY syndrome is a rare sex chromosome aneuploidy (SCA) characterized by neurodevelopmental deficits and medical comorbidities. The limited information available in the literature is almost exclusively limited to postnatally diagnosed cases. This study aims to describe the early medical and developmental features of prenatally identified 48,XXYY infants, with comparisons to 47,XYY, 47,XXY cohorts, and typical populations, as well as previously reported postnatally diagnosed 48,XXYY cases. Methods: The eXtraordinarY Babies Study prospectively follows children prenatally identified to be at high risk for SCA with annual medical and neurodevelopmental evaluations. Data presented herein include the prevalence of medical conditions, developmental milestones, developmental and adaptive functioning assessment scores, and therapy utilization in participants confirmed to have 48,XXYY. Comparisons were made between this cohort and the typical population, infants with 47,XYY and 47,XXY also enrolled in the eXtraordinarY Babies Study, and a 2008 cohort of individuals postnatally identified 48,XXYY. Results: Infants with 48,XXYY exhibited a range of early medical features, including high rates of feeding and GI disorders (breastfeeding difficulties, gastroesophageal reflux, and eosinophilic esophagitis), allergic disorders (food allergies and environmental allergies), and hypotonia. Developmental and adaptive functioning scores indicated delays in motor, communication, and social domains, with nearly all infants receiving speech therapy, physical and/or occupational therapy. Comparisons with the 47,XYY and 47,XXY cohorts revealed more medical and developmental challenges in the 48,XXYY group, however there was variability and some overlap with both the general population and sex chromosome trisomy conditions. Additionally, comparison to the 2008 postnatally identified 48,XXYY cohort indicated that while prenatal diagnosis allowed for earlier intervention, developmental outcomes in the first years of life were similar between the two groups. Conclusions: 48,XXYY diagnosed prenatally facilitates early monitoring, anticipatory guidance, and proactive referrals for medical evaluations and intervention, given developmental delays and medical challenges are more common in infancy and early childhood compared to the general population and trisomy SCAs. These findings provide valuable insights for genetic counselors and healthcare providers, emphasizing the spectrum of medical and developmental findings and importance of early and proactive care to support individual outcomes. Prospective study of this prenatally identified cohort will provide important natural history and phenotypic variability in XXYY, as well as identification of predictors of health and developmental outcomes.

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Benchmarking General-Purpose and Medical AI Large Language Models for Clinical Assessment and Management in Parkinson's Disease

Shechter, Y.; Klevor, R.; Kouchache, T.; Bouhadoun, S.; Postuma, R. B.

2026-05-20 neurology 10.64898/2026.05.13.26353021 medRxiv
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Background: The clinical applicability of large language models (LLMs) in Parkinson's disease (PD) management remains insufficiently characterized, particularly in generative responses to clinical vignette scenarios. Objective: To evaluate the quality of clinical assessments and management plans generated by a general-purpose LLM (Gemini 1.5 Pro) and a medically specialized LLM (OpenEvidence), and to compare their performance. Methods: Models generated free-text responses to 45 open clinical queries, focused on assessment of the situation, and recommended management plan. Two movement disorders fellows rated outputs using 5-point Likert scales, dichotomized into clinically appropriate ([&ge;]4) versus inappropriate ([&le;]3). Discrepancies were adjudicated by a senior movement disorders specialist. Paired comparisons used McNemar's test; qualitative analysis examined severe errors. Results: Gemini 1.5 Pro and OpenEvidence showed high rates of clinically appropriate assessments (80.0% vs. 86.7%) but lower performance in management plans (48.9% vs. 57.8%). Cases in which both assessment and plan were clinically appropriate occurred in 46.7% and 55.6% of cases, respectively. None of these differences reached statistical significance. Severe errors were uncommon in assessments (6.7% vs. 8.9%) but more frequent in plans (26.7% in both), predominantly reflecting treatment strategy errors. Conclusions: In generative clinical reasoning tasks involving Parkinson's disease management vignettes, LLMs demonstrated reasonable performance in assessment, but consistent limitations in plan generation. The medically specialized LLM demonstrated several qualitative advantages but no statistically significant performance benefit over the general-purpose model. Therefore, these tools should be used with appropriate caution in Parkinson's disease management, particularly regarding treatment recommendations.

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Who Supports the Caregivers? Perspectives on Mental Health Screening in Paediatrics.

Coscini, N.; Giallo, R.; Grobler, A.; Hiscock, H.; Mulraney, M.; Pope, N.

2026-06-08 psychiatry and clinical psychology 10.64898/2026.06.04.26354967 medRxiv
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Objectives To explore caregiver and clinicians perspectives on implementing mental health conversations and supports for caregivers of children with chronic conditions in paediatric outpatient clinics. Specifically, views were sought on (a) screening approaches and measures (phase 1) and (b) how feedback and support could be provided to caregivers experiencing mental health difficulties (phase 2). Methods Caregivers and clinicians from two outpatient clinics (neuromuscular and diabetes) at a tertiary paediatric hospital in Melbourne, Australia participated in online focus groups in July and August 2024. Caregivers were recruited from outpatient clinics and clinicians were recruited via email. Both groups were combined for phase 1 before separating into breakout rooms for phase 2. Two authors conducted reflexive thematic analysis of transcripts using NVivo. Results Sixteen participants (caregivers n = 8; and clinicians n = 8) took part in in two semi-structured focus groups. Analysis generated two overarching domains, each comprising multiple themes. Domain 1, Addressing caregiver mental health, captured themes of overwhelm and invisibility, diverse caregiving roles, and the need for time and resources to support wellbeing conversations. Domain 2, Housing the mental health conversation, encompassed themes of screening preferences, caregiver agency in confidentiality, delivery of feedback, and access to tailored supports. Conclusions Caregivers and clinicians support routine caregiver mental health discussions in paediatric outpatient settings. Caregivers favour screening at diagnosis and key transitions, with clear, and actionable feedback delivered away from the child. Questions about record-keeping warrant further exploration, as do the perspectives of fathers.

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Exploring healthcare experiences and access needs in unplanned hospital admissions for Inflammatory Bowel Disease: A multi-perspective qualitative study

Hawkins, R. L.; Cotterill, C.; McCormick, S.; Kellar, I.; Lobo, A. J.; Sampson, F. C.

2026-05-27 gastroenterology 10.64898/2026.05.26.26353596 medRxiv
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Background Unplanned hospital admissions in Inflammatory Bowel Diseases (IBD) account for nearly three-quarters of IBD inpatient stays in the United Kingdom. Although costly to services and distressing for patients, research exploring experiences and potential drivers of admissions is limited. We undertook a qualitative study to explore the healthcare experiences and access needs of people with IBD who had unplanned admissions, along with their caregivers and clinicians. Methods Semi-structured interviews with 25 participants from a single tertiary IBD service in England (17 people with IBD, 3 informal caregivers, 5 clinicians) were conducted. We applied thematic framework analysis, guided by the Candidacy Framework, and worked with 2 patient and public contributors to generate final themes. Results We identified four themes: 1) Difficulties in Identifying flares and asserting severity before admission, summarised the prevailing uncertainty in identifying a flare and access to timely IBD care. 2) Navigating a disjointed healthcare system, highlighted how lack of care plans and systemic barriers can delay access. 2) Emergency care access challenges highlighted the gaps in emergency and inpatient care during flares. Whilst 4) fighting for care and individual advocacy needs, described the persistent assertion for care that may disproportionally impact access to vulnerable groups, also highlighting the importance of positive interpersonal relationships. Conclusions Individual, interpersonal and healthcare factors across the patient pathway were perceived to shape access to care in unplanned IBD admissions. Potentially reducing admissions requires proactive strategies, including the integration of patient education, monitoring tools, establishment of specialist rapid-access pathways, and formal psychological support to address barriers to access.

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Language-Related Disparities in History Documentation in Patients Admitted for Heart Failure

Gottlieb, E. R.; Mullan, I. D.; Celi, L. A. A.

2026-05-22 cardiovascular medicine 10.64898/2026.05.19.26353593 medRxiv
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Introduction Patients hospitalized with heart failure who do not speak English as their primary language face communication barriers, however the impact on documented History of Present Illness (HPI) and Review of Systems (ROS) has not been reported. Methods This retrospective cohort study was based on MIMIC-IV, an anonymized clinical database. Adult patients admitted to general medicine or cardiology services with heart failure (by DRG) were identified. Multivariable linear regression was used to assess for an association between language (English vs. non-English) and word counts for HPI+ROS and HPI word counts. Qualitative differences in texts were also analyzed using Claude Opus 4.6. Results In a cohort of 552 patients, non-English language (N = 81) was associated with a shorter HPI+ROS (coef. -33.387, 95% CI [-62.076, -4.697], p = 0.023) controlling for age (coef. -1.023, 95% CI [-1.817, -0.230], p = 0.012) and Elixhauser score (coef. 10.391, 95% CI [7.078, 13.705], p<0.001). Similar associations were found for HPI alone. Qualitative differences included less discussion of symptoms and timing of onset. Discussion HPI+ROS and HPI were more abbreviated when the primary documented language was not English. This has important implications for equitable care and the development of emerging translation and documentation technologies.

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Post-Acute Rehabilitation Placement After Acute Ischemic Stroke Is Associated With Non-Clinical Factors Despite Similar Clinical Profiles

Hayes, H. A.; Zhang, C.; Xiang, S.; Smith, B.; Williams, P.; Presson, A.; French, M. A.

2026-05-12 health systems and quality improvement 10.64898/2026.05.08.26352775 medRxiv
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BackgroundDischarge destination after acute ischemic stroke has implications for functional recovery and healthcare costs. Individuals discharged to inpatient rehabilitation facilities (IRFs) achieve better outcomes than those discharged to skilled nursing facilities (SNFs); however, many patients discharged to IRFs and SNFs have similar clinical profiles. We examined non-clinical factors associated with discharge location after acute ischemic stroke. MethodsPopulation: 236 adults hospitalized with acute ischemic stroke, living independently in the community prior to admission, and discharged to either an IRF (n=171) or SNF (n=65). Clinical variables: NIHSS, Charlson Comorbidity Index (CCI), acute care length of stay (LOS), functional status (AM-PAC "6-Clicks"), and neglect. Non-clinical variables: age, sex, race, marital status, insurance, home layout, living status, and available assistance. Associations with discharge location were evaluated using univariable and multivariable logistic regression and reported as odds ratios (OR) with 95% confidence intervals (CI). ResultsIndividuals discharged to IRFs were younger, more likely to cohabitate, and had shorter LOS than those discharged to SNFs. Functional status (AM-PAC) and comorbidity burden (CCI) did not differ significantly between groups despite differences in discharge destination. In univariable models, younger age, cohabitating marital status, living with family, available assistance, shorter LOS, private insurance, and higher NIHSS were associated with greater odds of IRF discharge. In multivariable analysis, younger age (OR 0.94, 95% CI 0.91-0.98), cohabitating marital status (OR 2.46, 95% CI 1.13-5.48), and shorter LOS (OR 0.88, 95% CI 0.82-0.93) remained independently associated with IRF discharge. ConclusionsIndividuals with comparable pre-stroke independence and similar clinical severity, discharge to IRF versus SNF was independently associated with non-clinical factors; age, marital status, and LOS, whereas stroke severity and functional status were not significant predictors. These findings underscore the importance of evidence-informed discharge criteria integrating clinical indicators and social context to support equitable access to intensive rehabilitation after stroke.

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Population nuclear mitochondrial disease risk estimated from nuclear disease gene variants in a healthy older cohort

Watson, E. C.; Ravishankar, S.; Hobbs, M.; Copty, J.; Yu, C.; Kummerfeld, S.; Liang, C.; Lacaze, P.; Davis, R.; Sue, C. M.

2026-05-18 neurology 10.64898/2026.05.14.26353160 medRxiv
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Mitochondrial diseases (MDs) are genetically and phenotypically diverse and can be difficult to diagnose. Prevalence estimates derive largely from diagnosed cases and may underestimate population MD risk. Population-based studies are limited in scope and number but indicate MD variants are common. As genomic sequencing advances have made comprehensive population-based evaluation feasible, we sought to evaluate nuclear MD variation in a population cohort to understand variant prevalence and differences in MD risk estimates We identified disease-associated nuclear gene variants in 270 nuclear MD genes across 2,845 healthy older individuals in the Medical Genome Reference Bank. From Pathogenic or Likely Pathogenic Variants (PLPVs) we estimated autosomal recessive (AR) and autosomal dominant (AD) MD risk for individual genes and all nuclear variant-associated MDs. We identified 554 PLPV alleles representing 357 unique variants in 145 genes. Combined AR MD risk was estimated at 25.8 per 100,000 (95% CI 18.7 to 32.9), or 1 in 3,880 individuals. SPG7 (12.65 per 100,000; 95% CI 7.52-20.6) and POLG (4.23 per 100,000; 95% CI 2.10-8.01) contributed the greatest single gene AR MD risks and OPA1 variants posed the greatest AD MD risk. We observed a high rate of MD-associated nuclear gene variation in this healthy older cohort. The estimated lifetime AR MD risk was higher than commonly quoted prevalence estimates for all MDs, and the presence of common AD variants suggests variant penetrance may be lower than previously understood. These data help contextualise population MD risk and may inform clinical counselling and care.