Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. Conventional genetic diagnostics are low-throughput and may miss intronic, structural, or phenocopy variants, leading to delayed or missed diagnoses. In this study, we evaluate the utility of a custom next-generation sequencing (NGS) panel targeting the full-length ATP7B gene and 10 additional copper metabolism-related genes in patients with clinically suspected WD. We conducted a prospective cohort study of 144 individuals at our neurogenetic center. Variants identified by NGS were filtered and annotated with in silico tools and classified according to American College of Medical Genetics and Genomics guidelines. Confirmatory Sanger sequencing, multiplex ligation-dependent probe amplification, and reverse transcription PCR assays were performed as needed. Genetic confirmation of WD was achieved in 129 of 144 patients (90%), including 80 typical (Leipzig score ≥4) and 49 atypical (score <4) cases. Ten novel ATP7B variants, including deep intronic, noncanonical splice, and copy number variants, were identified using this panel. Among 15 genetically unresolved cases, 6 harbored variants in other copper metabolism-related genes but no pathogenic ATP7B variants. Notably, 1 patient with a Leipzig score of 4 had been clinically diagnosed with WD for years but was reclassified as spinocerebellar ataxia type 12 after panel testing revealed only a heterozygous CP variant and a CAG repeat expansion in PPP2R2B. Our comprehensive multigene NGS panel enables precise diagnosis of WD by detecting both classical and unconventional pathogenic variants, as well as distinguishing phenocopies. This improved diagnostic accuracy underscores the value of early genetic testing to guide timely intervention, especially in atypical or early-stage cases.

Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant adult-onset neurodegenerative disorder. Cases may appear sporadic when the family history is uninformative or relatives' symptoms are unrecognized as disease-related. We herein report a 49-year-old male with no family history of ataxia but with excessive alcohol consumption, initially diagnosed with alcoholic cerebellar degeneration (ACD) and subsequently identified as having SCA6. Diagnosing ACD is difficult because reliable diagnostic markers and threshold levels of alcohol intake predicting cerebellar degeneration are lacking. Alternative diagnoses, including SCA6, should be considered when clinical or imaging findings are atypical and the family history is uninformative.

Spinocerebellar ataxia type 10 (SCA10) is an autosomal-dominant disorder caused by intronic expansions of pentanucleotide repeats in the ATXN10 gene. While various repeat motifs have been described, emerging evidence suggests that specific repeat motifs, rather than repeat length alone, can modify disease features such as seizure prevalence and penetrance. We used a novel multiplex 20-gene panel with Cas9-targeted, amplification-free long-read sequencing (LRS) and optical genome mapping to elucidate ATXN10 repeat motif patterns and investigated genotype-phenotype correlations in index cases of 6 multigenerational SCA10 kindreds from Peru. We detected ATXN10 repeat expansions ranging from 990 to 2,002 pentanucleotide repeats (4.9-10 kb) across 6 families. It is important to note that we identified 3 mixed repeat motif patterns and ratios of (ATTCT)n(ATTCC)n, which were associated with differences in age at disease onset and anticipation. Our key novel finding is the prominence of the alternate ATTCC motif alongside the common ATTCT motif. While repeat length alone does not appear to drive disease onset in SCA10, we uncovered that the ratio of the ATTCC motif within distinct repeat patterns might correlate with disease onset. These findings underscore the need to adapt LRS clinical workflows to fully characterize large repeat expansions at the nucleotide level.

Spinocerebellar ataxia type 3 (SCA3) is characterized by extensive supra- and infra-tentorial brain injuries, beginning in the pre-symptomatic stage. However, the alterations and evolution of spontaneous brain activity in SCA3 patients remain poorly understood. This study aimed to investigate the abnormal brain activity of SCA3, classified it into distinct patterns, and explored the association between spontaneous brain activity in affected regions and clinical variables. Ninety-nine SCA3 patients (76 sym- and 23 pre-SCA3 patients, mean age: 39.97 ± 10.83y; 28.74 ± 7.99y) and 49 healthy controls underwent 3.0T MRI and acquired T1 and resting-state functional MRI images. The static and dynamic amplitude of low-frequency fluctuation (s/dALFF) and regional homogeneity (s/dReHo) were used to estimate local brain activity alterations. SCA3 patients exhibited significantly abnormal spontaneous brain activities in multiple regions, classified into four patterns (P < 0.001). Patterns 1 and 2 were found in the pre-symptomatic stage, involving the right opercular part of inferior frontal gyrus, right rolandic operculum, right insula, right angular gyrus, right crus I of cerebellar hemisphere and left superior frontal gyrus. Pattern 3 emerged in symptomatic SCA3, with expanded involvement of supra- to infra-tentorial regions. Pattern 4 showed increased activity in the right cerebellar lobule IX. Negative correlations were found between sReHo value in the right anterior cingulate cortex with the disease duration and severity (P ≤ 0.04). SCA3 patients exhibit different patterns of brain activity damage at different stages. These findings provide new insight into brain dysfunction in SCA3 and suggest potential imaging markers for disease staging and monitoring.

Ataxia-telangiectasia (A-T) is an inherited multiorgan disorder with onset in childhood. Liver involvement, with steatosis and subsequent fibrosis, is increasingly recognized in children and young people with A-T. To evaluate feasibility of T1-weighted two-point mDixon MRI for identification of liver steatosis in children with A-T and conduct exploratory analysis of relationships between MRI-quantified liver fat fraction and clinical and laboratory measures. Post hoc analysis of prospectively collected research data. 16 participants (8 female) with A-T aged 4.8-16.6 years. 3.0-T, two-point T1-weighted mDixon. Participants underwent whole-body MRI including T1-weighted mDixon. Water/fat signal percentage images were generated. Hepatic T1 fat fraction (T1-FF) was calculated from regions-of-interest placed in the right anterior, right posterior and left hepatic lobes. T1-FF > 5.56% was used as the diagnostic criterion for hepatic steatosis. Group comparisons of variables between participants with and without previous diagnosis of liver steatosis were made using independent sample Mann-Whitney U. Associations between T1-FF and age, neurological severity and of liver function tests were tested with Spearman correlation. Statistical significance was pre-specified as p < 0.05. Analyzable T1-weighted mDixon data was available for 11 participants. Five MRI datasets were discarded due to motion artefact (n = 3) or incorrect archiving of the original water image (n = 2). Median liver T1-FF was 11.3% (4.7-49.7%), and 10/11 (91%) of participants had evidence of steatosis. Participants with previous diagnosis of steatosis had higher T1-FF than those without (median 32.7% [9.7-49.7%], versus 10.3% [4.7-11.3%], p = 0.030). T1-FF correlated most strongly with alanine transaminase (r = 0.76, p = 0.007) and γ-glutamyltransferase (r = 0.76, p = 0.006). T1-weighted mDixon MRI is feasible for detecting steatosis in children with A-T, although motion artefacts reduced data completeness. MRI-quantified liver T1-FF correlates with markers of liver health. We found higher prevalence of liver steatosis using T1-weighted mDIXON than previously reported in pediatric A-T cohorts.