Abstracts

Rationale: The purpose of this study is to investigate rare genomic structural variants in epilepsy and identify candidate genes for epilepsy. Methods: We reviewed clinical and genetic data of 22 patients with epilepsy and rare pathogenic chromosome deletions, duplications and translocations. Results: The structural genomic variants identified included 15q duplications or deletions (8 cases), 4p deletions (3 cases), 10p15.3 deletion (1 case), 16p deletion (1 case), 2p deletion (1 case), 3p deletion (1 case), 1p36 deletion (2 cases), ring chromosome 20 (1 case), 20q11.2 duplication (1 case), 6p deletion (1 case), ring chromosome 6 (1 case), Xq26 duplication (1 case) and reciprocal translocation of chromosome 5 and 12 (1 case). One male with epilepsy and developmental delay had a deletion of 10p15.3 about 216 Kb in size. The deletion contained complete ZMYND11 (transcription repressor) gene region and promoter and 5’ regions of DIP2C gene (transcription factor). ZMYND11 and DIP2C are expressed in brain. One female with epilepsy had a duplication of 486.5 Kb and contained DNMT3B and KIF3B genes. DNMT3B is a de novo DNA methyltransferase and is involved in epigenetic modification of genes. Xq26 duplication contained GPC3 gene. Most frequent structural variation in our series was 15q deletions and duplications. Epilepsy associated with 15q11 duplications included infantile spasms and Lennox Gastaut syndrome. 15q duplications and deletions associated with epilepsy suggested a locus for epilepsy on 15q which is proximal to the Angelman syndrome and autism regions. Conclusions: Investigation of structural genomic variation is a useful way to identify candidate genes for epilepsy.