Search

Background: FRMD5 variants were recently identified in patients with developmental delay, ataxia, and eye movement abnormalities. Objectives: We describe 2 patients presenting with childhood‐onset ataxia, nystagmus, and seizures carrying pathogenic de novo FRMD5 variants. Weighted gene co‐expression network analysis (WGCNA) was performed to gain insights into the function of FRMD5 in the brain. Methods: Trio‐based whole‐exome sequencing was performed in both patients, and CoExp web tool was used to conduct WGCNA. Results: Both patients presented with developmental delay, childhood‐onset ataxia, nystagmus, and seizures. Previously unreported findings were diffuse choreoathetosis and dystonia of the hands (patient 1) and areas of abnormal magnetic resonance imaging signal in the white matter (patient 2). WGCNA showed that FRMD5 belongs to gene networks involved in neurodevelopment and oligodendrocyte function. Conclusions: We expanded the phenotype of FRMD5‐related disease and shed light on its role in brain function and development. We recommend including FRMD5 in the genetic workup of childhood‐onset ataxia and nystagmus. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

• Large NGS datasets enable the evaluation of the role of private variants in PD. • Gene-base burden analyses of private variants were performed in PRKN, PARK7 and PINK1. • Burden analysis of private variants in these genes yielded no association to PD risk. • Different Age-of-onset analyses did not reveal any further associations to PD risk. Recessive mutations in PRKN, PARK7, and PINK1 are established causes of early-onset Parkinson's disease (EOPD). Previous studies have interrogated the role of heterozygous variants in these genes but mainly focused on rare (minor allele frequency [MAF] <1%) damaging variants or established mutations. Here, we assessed heterozygous private PRKN, PARK7 and PINK1 variants in PD risk in four large-scale PD case-control datasets by performing gene-wise burden analyses using sequencing data totaling 5,829 PD cases and 7,221 controls, and summary allele counts from 9,501 PD cases and 48,207 controls. Results showed no significant burden in all three genes after meta-analyses. Burden in EOPD (age at onset <50 years) and late-onset PD (≥50 years) remained nonsignificant. In summary, we found no evidence to support the association of the excess burden of heterozygous private variants in PRKN, PARK7, and PINK1 with PD risk in the European population. Larger, more diverse cohorts are needed to accurately determine their role in PD. [ABSTRACT FROM AUTHOR]