Helmholtz Gemeinschaft


The phenotypic and genotypic spectrum of epilepsy and intellectual disability in adults: Implications for genetic testing

PDF (Original Article) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
[img] Other (Supporting Information)

Item Type:Article
Title:The phenotypic and genotypic spectrum of epilepsy and intellectual disability in adults: Implications for genetic testing
Creators Name:von Brauchitsch, S. and Haslinger, D. and Lindlar, S. and Thiele, H. and Bernsen, N. and Zahnert, F. and Reif, P.S. and Balcik, Y. and Au, P.Y.B. and Josephson, C. and Altmüller, J. and Strzelczyk, A. and Knake, S. and Rosenow, F. and Chiocchetti, A. and Klein, K.M.
Abstract:OBJECTIVE: The phenotypic and genotypic spectrum of adult patients with epilepsy and intellectual disability (ID) is less clear than in children. We investigated an adult patient cohort to further elucidate this and inform the genetic testing approach. METHODS: Fifty-two adult patients (30 male, 22 female) with epilepsy, at least mild ID and no known genetic or acquired cause were included and phenotyped. Variants identified through exome sequencing were evaluated using ACMG criteria. Identified variants were compared with commercially available gene panels. Cluster analysis of two features, age at seizure onset and age at ascertainment of cognitive deficits, was performed. RESULTS: Median age was 27 years (range 20-57 years) with median seizure onset at 3 years and median ascertainment of cognitive deficits at 1 year. Likely pathogenic/pathogenic variants were identified in 16/52 patients (31%) including 14 (27%) single nucleotide variants and 2 (4%) copy number variants. Simulated yield of commercial gene panels varied between 13% in small (≤144 genes) and 27% in large panels (≥1478 genes). Cluster analysis (optimal number 3 clusters) identified a cluster with early seizure onset and early developmental delay (developmental and epileptic encephalopathy, n=26), a cluster with early developmental delay but late seizure onset (ID with epilepsy, n=16) and a third cluster with late ascertainment of cognitive deficits and variable seizure onset (n=7). The smaller gene panels particularly missed the genes identified in the cluster with early ascertainment of cognitive deficits and later onset of epilepsy (0/4) as opposed to the cluster with developmental and epileptic encephalopathy (7/10). SIGNIFICANCE: Our data indicates that adult patients with epilepsy and ID represent a heterogeneous cohort that includes grown-up patients with DEE but also patients with primary ID and later onset of epilepsy. To maximize diagnostic yield in this cohort either large gene panels or exome sequencing should be used.
Keywords:Epilepsy, Genetics, Phenotype, Developmental and Epileptic Encephalopathy, Intellectual Disability, Adults, Genetic Testing
Source:Epilepsia Open
Page Range:497-508
Date:June 2023
Official Publication:https://doi.org/10.1002/epi4.12719
PubMed:View item in PubMed

Repository Staff Only: item control page


Downloads per month over past year

Open Access
MDC Library