American Journal of Medical Genetics Part A

CTNNB1 syndrome is a rare neurodevelopmental disorder caused by pathogenic variants in the CTNNB1 gene. Although its core clinical manifestations have been increasingly recognised, longitudinal data on cognitive, behavioural and motor trajectories remain limited, and the craniofacial phenotype has not previously been quantitatively characterised. This study provides longitudinal evidence on the cognitive, clinical and psychological profile of individuals with CTNNB1 syndrome, together with a detailed three-dimensional morphometric analysis of facial morphology. Cognitive, clinical, psychological and neuropsychological data were collected at two time points (T0 and T1), separated by a one-year interval, using a comprehensive and standardised assessment protocol. Longitudinal analyses indicated stability across most domains, with no evidence of systematic regression. A significant improvement in gross motor functioning was observed, particularly among younger participants. Linear mixed-effects models showed that age moderated developmental change, with younger individuals exhibiting greater gains over time in gross motor skills and adaptive behaviour compared to older participants. Three-dimensional facial morphometric analyses revealed a distinctive and statistically significant craniofacial pattern associated with CTNNB1 syndrome, independent of age and facial size. This phenotype was characterised by midfacial narrowing, reduced midface projection and mandibular retrusion. Importantly, facial shape variation was significantly associated with externalising behavioural problems and clinically relevant behavioural difficulties, suggesting a link between craniofacial morphology and behavioural severity. This study represents the first integrated longitudinal characterisation of CTNNB1 syndrome combining neurodevelopmental follow-up with quantitative craniofacial phenotyping. The findings indicate slow but progressive improvement in specific clinical domains during childhood and adolescence, alongside relative stability in global adaptive functioning, and highlight three-dimensional facial morphology as a sensitive structural biomarker for phenotypic stratification and clinical monitoring in CTNNB1 syndrome. Lay summaryThis study is the first to describe how children with CTNNB1 syndrome, a rare genetic condition that leads to global developmental delays, develop over time. We also performed advanced facial analysis to look for common facial features among patients.

Introduction: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a common congenital malformation with complex etiology involving both genetic and environmental factors. Epigenetic mechanisms may mediate environmental contributions, but separating genetic from environmental effects remains challenging. Methods: We present an epigenome-wide association study with 32 monozygotic and 22 dizygotic twin pairs discordant for NSCL/P on blood and saliva samples. Differential methylation analysis was conducted using linear models to identify CpG sites showing significant methylation differences between affected and unaffected twins followed by functional annotation and pathway enrichment analysis. Results: The top-ranked finding is a differentially methylated region comprising two CpG sites at the CYP26A1 locus, cg12110262 (P = 3.21x10-7) and cg15055355 (P = 1.39x10-3). CYP26A1 is essential for retinoic acid catabolism and craniofacial patterning. The chromatin regulator ANKRD11, which causes KBG syndrome featuring cleft palate was the second best hit. Differentially methylated CpG sites showed significant enrichment in craniofacial enhancers and overlap with multiple GWAS-validated cleft genes including VAX1, PVRL1, SMAD3, and PRDM16. Conclusions: Our findings implicate retinoic acid signaling and chromatin regulation in NSCL/P etiology and demonstrate the value of discordant twin designs for distinguishing environmental from genetic epigenetic contributions to complex malformations.

Genetic counselling outcome measures are increasingly adapted for diverse clinical contexts. While the Genetic Counselling Outcome Scale (GCOS-24) is available in Swedish, no autism-specific version has been developed. Therefore, we adapted the Swedish GCOS-24 using the English version of the modified GCOS-24 (mGCSOS-24) to create a Swedish autism-specific mGCOS-24. Thereafter, we evaluated both the Swedish autism mGCOS-24 and the Swedish general GCOS-24 using Rasch analysis to assess their psychometric properties. Both instruments exhibited structural challenges, including multidimensionality, disordered thresholds, local item dependence, and invariance issues. For the Swedish autism mGCOS-24, we were able to identify subscales with acceptable measurement properties. However, applying the same structure to the Swedish general GCOS-24 did not resolve its broader limitations. This study introduces the first Swedish autism-specific mGCOS-24 and represents the first Rasch-based evaluation of any GCOS-24 or mGCOS-24 in Swedish. Our findings highlight important opportunities for measure refinement but also indicate that new or more substantially adapted tools may be needed to capture outcomes of genetic counselling in autistic populations.

Background: Diagnosing the over 700 known rare bone diseases (RBDs) is inherently challenging and often requires extensive time and multiple clinical visits. Effective treatment, particularly for RBDs with approved therapies, depends on early and precise identification of the specific RBD type. Image recognition artificial intelligence (AI) has the potential to significantly enhance diagnostic processes and improve patient outcomes. Many of these disorders cause characteristic skeletal changes, especially in the hands, and are associated with growth abnormalities. Consequently, affected children routinely undergo hand radiographs for bone age assessment, making these images a widely available yet underutilized diagnostic resource. Materials and Methods: We retrospectively compiled 5,623 multi-institutional hand radiographs from 2,471 patients with 45 different RBDs and 1,382 unaffected controls. We trained two deep learning models: a binary classifier to differentiate between RBD and non-RBD hand radiographs, and a multi-class classifier covering ten RBDs (or RBD groups), using 5-fold cross-validation. Preprocessing included masking, normalization, and data augmentation. Additionally, we applied occlusion sensitivity mapping to visualize class-specific features and evaluated the learned representations through cosine-based retrieval and UMAP projections of the feature space. Results: The affected versus unaffected classifier achieved a balanced accuracy of 85.5% on the test dataset. The ten-class classifier reached a balanced (top-1) accuracy of 76.6%, with top-3 accuracy exceeding 90%. Disorders with highly distinctive phenotypes, such as achondroplasia, achieved accuracies above 95%, whereas phenotypically overlapping disorders, such as ACAN- and SHOX-related short stature, were more frequently confused. Feature space analysis showed that validation samples clustered closely with their respective training distributions, supporting the consistency and generalizability of the learned embeddings. Conclusion: This manuscript presents a proof of principle for the development of Bone2Gene, a next-generation phenotyping (NGP) tool for the detection and differential diagnosis of RBDs, currently based on hand radiographs. Ongoing efforts focus on expanding the dataset to include additional RBDs or RBD groups in the current multi-class classifier for differential diagnosis and to further evaluate its generalizability. The Bone2Gene study is open to collaboration.

BackgroundExome sequencing (ES) has become a key diagnostic tool for rare diseases (RDs). However, most evidence on ES performance comes from high-income countries and patients from European ancestry. In countries such as Chile, limited access to next generation sequencing amplifies health disparities and highlights the need to identify which patients are most likely to benefit from ES. MethodsThis study presents the second phase of the Chilean DECIPHERD project, in which we performed ES in a new group of patients with RDs presenting with multiple congenital anomalies (MCA), neurodevelopmental disorders (NDD), and/or suspected inborn errors of immunity. To identify clinical and demographic factors associated with an increased probability of obtaining an informative ES result, we conducted a logistic regression analysis, combining the results of the first and second phases of the project. We also objectively evaluated global ancestry measured using ADMIXTURE, as a potential factor. ResultsSixty-seven patients participated in this second phase of DECIPHERD with a median age of 6 years (range: 0-27); 55.2% were female, with an average ({+/-} s.d.) proportion of Native American ancestry of 0.615 {+/-} 0.18. Clinically, 52.2% presented with both MCA and NDD, and the rest had other phenotype combinations. An informative result, including pathogenic or likely pathogenic variants in genes consistent with the patients phenotype, was identified in 34.3% of the cohort; 61% of these variants had not been previously reported in databases such as ClinVar. By combining the two phases of the study, we reached a total of 167 patients, in whom the presence of NDD and/or MCA significantly increased the probability of achieving an informative ES outcome. In contrast, previous use of gene panel testing was associated with a decreased likelihood of receiving an informative result. Ancestry was not associated with diagnostic yield. ConclusionsThis study demonstrates the utility of ES in achieving a diagnosis in a clinically diverse cohort of Chilean patients with RDs, and characterized features associated with a higher diagnostic yield. These findings may contribute to evidence-based patient prioritization strategies in settings with limited access to NGS resources.

Objective The decline of the perinatal demise rate is slowing and demises are often unexplained. Significant research has been done regarding diagnostic yield and genetic causes of demise, but little is known about how Geneticist involvement impacts outcomes. The goal of the study was to evaluate post-mortem genetic testing practices and effects of the geneticists involvement. Methods Retrospective data from 111 perinatal demise cases was examined, including rates of prenatal genetic counseling, post-delivery genetics consult, genetic testing, and autopsy investigation. Results In this cohort 54% received genetic testing and 25% received a genetics consult. When compared to those without, cases with genetic specialist involvement were associated with significant increases in testing uptake (p=0.007), diagnostic yield (p<0.001), and patient education (p<0.001). Second trimester stillbirths and those with fewer ultrasound (US) abnormalities were less likely to receive genetic testing (both p values <0.001) and consults (p<0.001, p=0.020). Conclusion Though it was not possible to avoid ascertainment bias, this data demonstrates that geneticist involvement correlates with a higher rate of testing, greater diagnostic yield, and more thorough counseling. These findings underscore the importance of integrating genetics providers into perinatal postmortem healthcare teams.

Wolfram syndrome is a rare genetic disorder characterized by antibody-negative early-onset atypical diabetes mellitus, optic nerve atrophy, sensorineural hearing loss, diabetes insipidus (arginine vasopressin deficiency), and progressive neurodegeneration, with significant variability in disease severity. We assessed the accuracy of a genotype-based severity scoring system to predict the onset of cardinal symptoms in Wolfram syndrome. This system is based on the type of WFS1 variants (in-frame or out-of-frame) and their location relative to transmembrane domains. Severity scores were assigned to 324 patients with documented onset ages for diabetes mellitus, optic atrophy, hearing loss, and diabetes insipidus. Our analysis revealed a clear correlation between severity scores and earlier onset of diabetes mellitus and optic atrophy. Patients with in-frame variants outside transmembrane domains exhibited milder symptoms, especially WFS1 c.1672C>T (p.Arg558Cys) variant, whereas those with out-of-frame variants showed the earliest onset. Severity scores 3 and 4 did not follow the expected progression, suggesting that transmembrane domain involvement in both alleles may result in greater severity. These findings suggest that this scoring system provides valuable insights into the progression of Wolfram syndrome and may guide clinical care. Further refinement may improve its utility for predicting the onset of non-diabetic symptoms.

Background: Despite strong evidence from controlled trials, uncertainty remains about the real-world use of 0.05% atropine in patients with lighter irises due to tolerability concerns, and predictors of treatment response are poorly understood. Here, we evaluated the effectiveness, tolerability, and early biometric response to 0.05% atropine in clinical practice among patients with predominantly light irises. Methods: This prospective cohort study included 33 patients treated with 0.05% atropine (82% with light irises). Cycloplegic spherical equivalent refraction (SER) was measured at baseline and 3-month intervals. Axial length (AL), photopic pupil diameter, accommodation amplitude, and subjective side effects were monitored more frequently initially. Results: Median age at treatment initiation was 11.97 years, SER -5.38 D, and AL 25.42 mm. Over 12 months, SER changed by -0.078 {+/-} 0.349 D (mean {+/-} SD), and AL increased by 0.052 {+/-} 0.115 mm. Eighty-eight percent of participants had a SER change of <0.5 D, and 91% had axial elongation of <0.2 mm, indicating clinically limited myopia progression. Photopic pupil diameter was larger, and accommodation amplitude was reduced throughout follow-up. Early in treatment, side effects, including photophobia and near-work difficulties, were common but minimally disruptive. Their incidence decreased rapidly and rarely required treatment modification. In exploratory analyses, early AL changes predicted 12-month AL outcomes, with associations detectable as early as 1 week and strengthening over time. Conclusions: 0.05% atropine was well tolerated and effective in this population with light irises. Early AL changes may predict 12-month treatment response. These findings support the implementation of 0.05% atropine in routine clinical practice in populations with light irises and highlight the potential for early AL monitoring to guide timely treatment adjustments.

Abstract Background Understanding the phenotypic spectrum of disease-associated genes is essential for accurate diagnosis and targeted therapy. FRMPD4 (FERM and PDZ Domain Containing 4) has previously been associated with intellectual disability and epilepsy. However, its potential role in non-syndromic hearing loss has not been explored. Methods We performed genetic analysis in two unrelated families presenting with non-syndromic sensorineural hearing loss, identifying maternally inherited missense variants in FRMPD4. Clinical phenotyping included audiological assessment and evaluation for neurodevelopmental involvement. Cross-species expression analyses were conducted in Drosophila, zebrafish, and mouse. Functional characterization included quantitative evaluation of sound-evoked responses in Drosophila nicht gut hoerend (ngh) mutants, assessment of neuronal development and acoustic startle responses in zebrafish loss of function models, and morphological cochlear analyses with auditory brainstem response measurements in knockout mice. Results Three affected males from two unrelated families presented with prelingual, bilaterally symmetrical sensorineural hearing loss, with confirmed congenital onset in one individual and no evidence of neurodevelopmental abnormalities. Cross-species analyses demonstrated evolutionarily conserved expression of FRMPD4 in auditory structures. In Drosophila, quantitative analysis of sound-evoked responses in ngh mutants revealed impaired auditory function. Zebrafish loss of function models exhibited reduced neuronal populations in the otic vesicle and posterior lateral line, abnormal neuromast development, and diminished acoustic startle responses. In mice, Frmpd4 knockout resulted in high-frequency hearing loss and cochlear abnormalities consistent with the human phenotype. Conclusions Our findings expand the phenotypic spectrum of FRMPD4 to include non-syndromic sensorineural hearing loss and establish its evolutionarily conserved role in auditory function. These results have direct implications for genetic diagnosis and variant interpretation in patients with hearing loss.

Copy number variants (CNV) contribute significantly to the pathogenic variation associated with developmental disorders. CNV detection is often not included in standard exome sequencing (ES) analysis. Complementary methods such as chromosomal microarray are typically offered in diagnostic laboratories to diagnose pathogenic CNV. In this study, we aimed to develop an optimal approach for incorporating CNV detection within our ES analysis process for the Deciphering Developmental Disorders in Africa (DDD-Africa) cohort. We analyzed ES data from 505 probands with a developmental disorder, applying a CNV detection approach that assessed data generated using the tools CANOES and XHMM. When available, parental ES data was used to assess inheritance patterns. We confirmed a diagnosis in 42/505 (8,3%) patients with 44 pathogenic CNV identified in the probands. There were 31 deletions and 13 duplications. Among the 27 probands with parental data, all identified CNV were de novo. The addition of CNV analysis to our ES analysis pipeline resulted in an 8.3% increase in diagnostic yield in the DDD-Africa cohort without additional laboratory cost. This approach offers a feasible approach which is likely to reduce analytical cost and is suitable for low- and middle-income countries where funding and resources for genomic medicine initiatives are limited.

PIK3CA-related overgrowth spectrum (PROS) comprises a heterogeneous group of disorders caused by postzygotic activating variants in PIK3CA, leading to mosaic activation of the PI3K pathway. PROS natural history is highly variable across patients and depends on the timing and distribution of the somatic mutation. To better characterize this natural history, we analyzed a cohort of patients with PROS. This multicenter study was conducted at Hopital Femme Mere Enfant (Lyon, France) and Hopital Necker-Enfants Malades (Paris, France). We included pediatric and adult patients with PROS who had a documented PIK3CA variant and at least two MRI examinations performed at least 2 months apart. Patients undergoing interventional surgical or radiological procedures, or receiving targeted therapies were excluded. In all patients, target lesions were identified on baseline MRI scans, and assessed on follow-up scans according to the RECIST criteria. Among 67 PROS patients screened from 2008 to 2021, 30 met the inclusion criteria, including 43.3% female patients. The median age at first MRI was 19 years (interquartile range, 5 to 34) and the median interval between the two scans was 75.7 months (range, 2.1 to 160.3 months). Recurrent localizations included the face (n = 6; 20%), ear, nose and throat region (n = 3; 10%), upper limbs (n = 5; 16.7%), thorax (n = 3; 10%), abdomen (n = 4; 13.3%), pelvis (n = 5; 16.7%), and lower limbs (n = 10; 33.3%), with some patients presenting multisite involvement. During the observation period, 86.6% (n = 26) of patients exhibited an increase in target lesion volume, with a median progression of 37.8% (range, 2.6 to 233.0%) and a mean progression of 52% (standard error of the mean, 7.2%), reflecting a right-skewed distribution driven by a subset of rapidly enlarging lesions. In conclusion, this study provides the first radiological description of the natural history of PROS, demonstrating that tissue malformations most often enlarge over time, with sustained progression persisting into adulthood.

Neuroligin-3 (NLGN3) was first identified as a risk gene associated with autism spectrum disorder (ASD). The initial variant, p.R451C, associating NLGN3 with ASD has been heavily investigated, yet little is known about the functional consequences of other NLGN3 variants. Furthermore, while most of the identified variants are present in males with maternally inherited variants from unaffected mothers, several de novo variants were observed in females, suggesting a possible functional difference between de novo and maternally inherited variants. To address the functional consequences of NLGN3 variants in vivo, we generated transgenic Drosophila models corresponding to one de novo variant (p.R175W) identified in one female proband, and two maternally inherited variants (p.R451C and p.R597W) identified in male probands. In Drosophila, loss of the fly homolog, Nlg3, altered sleep patterns, synaptic architecture, and vesicle dynamics, which were rescued by the expression of the human NLGN3Ref allele. When comparing the variants, the de novo p.R175W variant and the maternally inherited p.R451C variant altered synapse morphology and sleep patterns, with minimal effects on vesicle dynamics, and the p.R597W variant altered sleep and vesicle dynamics with minimal impact on synapse morphology. Using overexpression models, human NLGN3Ref altered sleep patterns and synaptic morphology. Moreover, the p.R175W variant exacerbated sleep phenotypes, and the p.R175W and p.R451C variants exacerbated synapse morphology phenotypes. Together, our findings suggest that de novo NLGN3 variants identified in females are likely gain-of-function, while maternally inherited variants have mixed loss-and gain-of-function effects. Moreover, the location of the variants may contribute to the distinct functional differences we observed. Some NLGN3 variants disrupt synaptic development, while other variants alter synaptic function, suggesting that NLGN3 variants have differential effects. These functional differences may provide insight into the heterogeneity of individuals with ASD. Author SummaryAutism spectrum disorder (ASD) is a common neurodevelopmental disorder. Mutations in the Neuroligin-3 (NLGN3) gene are associated with ASD but very few of these mutations have been characterized in animal models. Most of these mutations affect male individuals who maternally inherited their genetic mutation; however, more rarely female individuals may present with a genetic mutation that was not identified in either of the parents. Here, we utilized the fruit fly model to investigate how three different mutations, one mutation identified in a female and two mutations identified in males, affect the flys behavior and synapse development. We identified altered sleep patterns in some of our mutants which is consistent with sleep disturbances being highly comorbid with ASD. Additionally, we identified alterations in synapse development and function which is consistent with the role of NLGN3 in synapse formation and maturation. Together, our findings support that NLGN3 is important for regulating the synapse and mutations in this gene can alter its function. However, different mutations can have differential effects. This demonstrates the need to assess multiple variants simultaneously because each variant may have distinct functional significances.

IntroductionNeuromuscular disorders (NMDs) encompass a broad group of conditions that primarily affect the peripheral nervous system. They are often caused by genetic alterations that impair skeletal muscle function and result in debilitating symptoms. Obtaining an accurate molecular diagnosis remains a challenge, potentially because variants in genes that have yet to be identified as causal. We therefore used advanced computational methods to study the genetic architecture of NMDs and to identify key features that distinguish NMD genes from other genes in the broader genome. MethodsCurated genes implicated in NMDs (n = 639; GeneTable of NMDs) were obtained and merged with a comprehensive set of genomic features for human autosomal protein-coding genes. Machine-learning-based feature selection and ranking were performed using Boruta, along with complementary analytical approaches. These analyses were used to identify the most important genic features (n = 134, subcategories: gene complexity, genetic variation, expression patterns, and other general gene traits) for discriminating NMD genes from other genes in the genome ResultsNMD genes exhibit enriched expression in disease-relevant tissues, including skeletal muscle and heart. Additionally, compared with other protein-coding genes, these genes exhibit increased transcriptomic complexity (e.g., longer transcripts and more unique isoforms), contain more short tandem repeats, and show greater variation in conservation across model organisms. ConclusionsThis study identified several key genomic features that may distinguish NMD genes from the rest of the genome. This may enhance the identification of novel causal genes and could ultimately facilitate earlier diagnosis and medical management for affected individuals.

Interpreting HNF1B variants is challenging in clinical practice. We aimed to integrate functional, clinical, and family data to improve variant classification, describe clinical features of carriers and report registry-level prevalence of HNF1B alterations. Clinical, genetic, and family data were analyzed from the Norwegian MODY Registry (NMR) and the Norwegian Childhood Diabetes Registry (NCDR). Clinical features of sequence variant and 17q12 deletion (17q12del) carriers were summarized, and variants were classified using ACMG-AMP-ClinGen criteria. Registry-level prevalence was reported with 95% confidence intervals. HNF1B sequence variants were functionally assessed, showing that the lower transactivation (TA) was associated with higher clinical severity. Eleven variants demonstrated impaired functional activity, with TA inversely correlated with clinical burden ({varrho} = -0.701, p = 0.002). We identified 28 individuals with 17q12del (21 in NMR, seven in NCDR) and 15 individuals carrying 14 unique (LP/P) sequence variants, all detected in the NMR. Overall, 36/486 probands (7.4%) with genetically confirmed monogenic diabetes in the NMR carried an LP/P HNF1B sequence variant or 17q12del. In the NCDR, [~] 0.2% carried 17q12del (7/3,583; 3/7 GADA/IA-2A-positive). Functional data enabled reclassification of three variants. Since many pediatric 17q12del carriers in the NMR were referred for testing due to structural renal anomalies without diabetes, HNF1B screening should be considered in children with renal/extra-renal features, irrespective of diabetes or autoantibody status. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=86 SRC="FIGDIR/small/26348894v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@41feforg.highwire.dtl.DTLVardef@ccc48borg.highwire.dtl.DTLVardef@17ba2e9org.highwire.dtl.DTLVardef@4919b_HPS_FORMAT_FIGEXP M_FIG C_FIG

ObjectivesTo screen the entire genome for genes associated with risk for lateral epicondylopathy and improve understanding of underlying biological mechanisms and inform future research aimed at risk stratification and personalized prevention and treatment strategies. MethodsA genome-wide association study was conducted using UK Biobank data. Lateral epicondylopathy cases were identified based on electronic health records from individuals of European ancestry. Logistic regression tested associations between single-nucleotide polymorphisms and disease status, adjusting for sex, age, height, weight and ancestry principal components. Previously-identified candidate genes from the literature were also tested for association with lateral epicondylopathy. ResultsAmong 20,390 cases of lateral epicondylopathy, two loci reached genome-wide significance: one comprising 144 linked SNPs and one single SNP. The first locus, led by rs13127477 (p=7.7x10-12; OR 0.93, 95% CI 0.91 to 0.95), is located near three SIBLING genes (IBSP, MEPE and SPP1) involved in extracellular matrix remodelling at fibrocartilaginous entheses. The risk allele was associated with increased SIBLING gene expression, suggesting that excessive entheseal matrix remodelling contributes to disease susceptibility. The second locus was defined by rs138254824 (p=3.69x10-8; OR 3.42, 95% CI 2.23 to 5.25) near NEDD9 and TMEM170B. Previously reported collagen gene associations were not replicated. ConclusionIn the first genome-wide screen for lateral epicondylopathy, two loci were identified. These loci provide insight regarding the pathophysiology of lateral epicondylopathy and a roadmap for preventing and treating this injury with personalized medicine. Summary BoxO_ST_ABSWhat is already known on this topicC_ST_ABSLateral epicondylopathy is a common and disabling overuse tendon condition, yet its genetic basis has remained poorly characterised, with prior studies limited to small candidate gene analyses. What this study addsThis study provides the first genome-wide association analysis of lateral epicondylopathy, identifying two risk loci on chromosomes 4 and 6 and implicating SIBLING genes (IBSP, MEPE, and SPP1) involved in entheseal extracellular matrix remodelling. How this study might affect research, practice or policyThese findings offer new biological insight into disease susceptibility and challenge previously reported collagen gene associations.

Heterozygous FOXL2 (non-)coding sequence and structural variants (SVs) lead to blepharophimosis, ptosis and epicanthus inversus syndrome (BPES), a rare, autosomal dominant developmental disorder characterized by a completely penetrant eyelid malformation and incompletely penetrant primary ovarian insufficiency (POI). We collected variants from our in-house database, generated via clinical genetic testing and downstream research testing in the Center for Medical Genetics Ghent, Belgium (2001-2024), and via literature and other resources in the same period. All retrieved variants were categorized using ACMG/AMP classifications to increase the knowledge of pathogenicity. We collected 413 unique genetic defects of the FOXL2 region, including 76 novel variants, in 864 index patients. Of these, 87% of patients were identified with a coding FOXL2 sequence variant. The polyalanine tract is a known mutational hotspot of FOXL2, illustrated here by the high percentage of pathogenic polyalanine expansions (24%). Furthermore, the molecular spectrum in typical BPES index patients is characterized by 8% coding deletions and 3% deletions located up- and downstream of FOXL2. The remaining 2% carry translocations along with chromosomal rearrangements of 3q23. This uniform and structured reclassification, incorporating the largest dataset of variants implicated in FOXL2-associated disease so far, will improve both the diagnosis as well as genetic counselling for individuals with BPES.

Adenylosuccinate synthetase 1 (ADSS1) myopathy is an ultra-rare disease characterized by progressive muscle dysfunction. The objective of this investigation was to employ a non-invasive biomarker approach to phenotype (fine-)motor skills, speech production and cognition in adults with ADSS1 myopathy. Five individuals with ADSS1 myopathy and five age-sex-matched healthy controls (HCs) underwent a comprehensive multimodal evaluation. Assessments included, (i) evaluation of motor performance, (ii) speech production and cognitive test batteries, (iii) patient-reported outcomes, (iv) electrical impedance myography (EIM), (v) musculoskeletal magnetic resonance imaging (MRI) and (vi) plasma proteomics. ADSS1 participants vs. HCs demonstrated reduced performance on the 9-Hole Peg and grip strength tests as well as lower self-reported mobility. Speech production analysis revealed asthenia (p=0.02), lower intelligibility (p=0.008), and worse voice quality during the sustained vowel task (p=0.03) in the ADSS1 cohort. Cognitive functioning remained unaffected in patients with ADSS1. On EIM, ADSS1 participants vs. HCs, demonstrated a pattern of higher resistance and lower reactance and phase across upper- and lower-extremity measurements, indicative of poorer muscle health, with large effect sizes (Cliffs 8=0.5-0.9). MRI revealed intramuscular fat infiltration, particularly in posterior compartments of the upper leg (e.g., biceps femoris). Proteomics indicated reduced (p=0.04) Neurotrophin-3 (NTF3; implicated in neuronal development, survival and differentiation) levels in the ADSS1 cohort relative to HCs. Lower NTF3 levels associated with poorer performance on hand-motor tasks as well as higher resistance and lower reactance and phase on EIM. This study highlighted the value of multimodal phenotyping for quantifying disease expression and advancing monitoring strategies in ADSS1 myopathy. Take-home messageThis multimodal investigation demonstrates that integrating electrical impedance myography with quantitative motor, speech, musculoskeletal imaging, and proteomic assessments provides a sensitive and non-invasive research framework for capturing neuromuscular dysfunction and functional disease burden in patients with ADSS1 myopathy, thereby supporting the current biomarker strategy for refined phenotyping and longitudinal disease monitoring in this ultra-rare condition.

The causes of severe neuropsychiatric deteriorations among patients with previously stable autism spectrum disorder (ASD) are poorly understood and present substantial challenges for care. We aimed to characterize the prevalence of autoimmune and inflammatory conditions and markers, as well as musculoskeletal findings, among youth with ASD experiencing a suspected post-infectious neuropsychiatric deterioration. The Stanford Immune Behavioral Health (IBH) Clinic is a specialty program for youth with neuropsychiatric deteriorations that are suspected to be post-infectious (non-psychosocial). We report findings for 43 consecutive patients with ASD (70% male [30 of 43]) evaluated in the IBH Clinic. The average (SD) age at clinical presentation was 12.0 (4.0) years. Juvenile arthritis was diagnosed in 15 patients (35%), predominantly enthesitis-related arthritis (ERA) and psoriatic arthritis (PsA). Seven patients had ultrasonographic evidence of joint effusions and/or synovitis without meeting juvenile idiopathic arthritis (JIA) criteria. Autoimmune conditions other than arthritis were observed in 9 patients (21%). The mean (SD) age at arthritis and other autoimmune condition diagnoses were 16.2 (5.5) and 12.7 (4.9) years, respectively. We observe markers of immune activation during neuropsychiatric deteriorations in over half of patients (60% [26 of 43]), including markers of autoimmunity (33% [12 of 36]), complement activation (41% [13 of 32]), immune dysregulation/inflammation (11% [4 of 37]), and vasculopathy (30% [13 of 43]). One-third (37% [16 of 43]) demonstrated two or more markers. These data underscore the importance of targeted immune evaluation--including musculoskeletal imaging and inflammatory marker screening--in ASD patients who have had a suspected post-infectious behavioral regression. Lay SummaryIn this cohort study of 43 patients with autism spectrum disorder (ASD) and suspected post-infectious deteriorations, more than half had laboratory markers of immune activation (using a limited panel), one-third had joint inflammation (confirmed by ultrasound), and additional autoimmune conditions were observed in 21%. From this, we conclude that patients with ASD who experience a suspected post-infectious neuropsychiatric deterioration may have underlying inflammation which may contribute to neuropsychiatric and behavioral regressions, highlighting the importance of immunologic and rheumatologic evaluation in clinical assessment.

IRF2BPL-related disorder is a neurodevelopmental disorder caused by heterozygous variants in the IRF2BPL (Interferon Regulatory Factor 2 Binding Protein-Like) gene. The few reports available in the literature suggest that common symptoms include developmental delay, intellectual disability and developmental regression. There are no reports of genotype-phenotype correlations. We developed a retrospective and prospective patient-reported survey to assess diagnostic information, presenting symptoms and longitudinal follow-up of neurological symptoms for up to two years. Clinical information was available for all 32 participants and was highly variable in regards to age at symptom onset, severity of neurologic manifestations, and progressivity. For 27 of the 32 participants, diagnostic genetic test results were available. Genetic mutation analysis revealed 22 individuals with truncating variants and five participants with unique missense variants in IRF2BPL. The study data support the hypothesis that IRF2BPL missense variants are associated with a less severe disease presentation and progression than participants with truncating variants. The purpose of this study is to further define IRF2BPL-related disorder and provide more clinical and molecular insight into this ultra-rare disease. Highlights- Patient-reported clinical history at diagnosis and up to two years of follow up - The clinical spectrum is increasingly heterogeneous - We report 32 patients, 27 with noted IRF2BPL variants, 14 being novel to literature. - Data supports the notion that IRF2BPL missense variants may be associated with less severe disease than truncations (nonsense/frameshifts).

Background: Facioscapulohumeral muscular dystrophy (FSHD) is a common hereditary neuromuscular disorder. The Russian FSHD Patient Registry was established in 2019 following the development of a PCR-based method for genetic confirmation of the diagnosis. Results: The registry included 470 participants (51% male). Genetic confirmation was obtained for 76% (n=356), the remainder were included based on clinical and anamnestic data. Clinical assessment forms and patient-reported questionnaires were analyzed for 310 and 142 patients, respectively. D4Z4 repeat unit (RU) distribution showed patterns consistent with European cohorts, with a predominance of patients with 3 RUs. A moderate inverse correlation was found between RUs number and clinical severity scales. Periscapular weakness was the most common onset manifestation (46.8%), followed by facial weakness (31.6%) which was often unnoticed by patients. The mean age in the Russian cohort was 37.8 years (range 0-97), indicating a younger cohort compared to international data. A delta-adjusted cluster analysis (n=215) identified three distinct trajectories: a classic phenotype with onset before age 14 and early involvement of various muscle groups (n=177), and two clusters characterized by either facial or periscapular onset with slow progression. Conclusion: The Russian FSHD registry provides a comprehensive characterization of a large national cohort, revealing a predominance of patients with 3 D4Z4 repeats and a younger demographic profile compared to international data. Cluster analysis identified three heterogeneous disease trajectories, offering a framework for improved patient stratification.