Long-read sequencing of the ATP7B gene from Moroccan patients with suspected Wilson disease

BackgroundWilson disease (WD) is an autosomal recessive disease caused by loss of function of the copper transporter encoded by the ATP7B gene. Clinically, it mainly leads to hepatic failure and neuropsychiatric manifestations. Information about epidemiology, diagnosis, treatment, and survival of WD in Morocco is scarce. This study aimed to assess the feasibility of long-read sequencing using Oxford nanopore technology (ONT) of the coding and non-coding regions of the ATP7B gene in populations with limited access to genetic testing, such as the Moroccan population. Methods and ResultsWe designed five long-range PCR primer pairs to amplify fragments approximately 15 kb long, encompassing the entire ATP7B gene. Barcoded libraries were prepared and sequenced via ONT flow cells (R10.4.1) using an Mk1C device. Our novel long-read ONT method was applied to 15 Moroccan patients clinically diagnosed with WD. This approach allowed the comprehensive detection of all single-nucleotide variants within the ATP7B gene. We identified 12 pathogenic variants, including a novel Alu insertion (c.1870-9_10ins) in intron 5, which is predicted to disrupt normal RNA processing and thereby cause WD. In all but one patient, the likely causative variants were identified, either in the homozygous or compound heterozygous state. ConclusionOur study demonstrates the versatility, affordability, and potential benefits of this methodology for the widespread implementation of ATP7B screening and diagnostic programs in WD patients from populations that have not yet been investigated. This is especially important for diseases that frequently exhibit heterozygote composites in genetically underexplored populations.