Epilepsies in Children with 2q24.3 Deletion/Duplication

More than 100 cases of deletions or duplications of the long arm of chromosome 2 have been reported. Deletion and duplication ranges vary markedly among individual patients. The relationship between range of deletion/duplication and phenotype is not well understood, although seizures and facial dysmorphism are observed commonly in patients with 2q21q31 deletions. Array comparative genomic hybridization (CGH) is useful to determine copy number variants (CNVs) and to investigate the relationship between CNV and phenotype. Recent studies using array CGH have provided insight into the genetic origin of the phenotypes of patients with CNV in 2q. The 2q24.3 region has attracted attention because three genes encoding a sodium channel, that is, SCN1A, SCN2A, and SCN3A, are located within this region. Mutations in SCN1A are an established, major genetic determinant of Dravet syndrome (DS), genetic epilepsywith febrile seizure plus (GEFS þ ), and other epilepsiesmostly refractory against antiepileptic drugs.1–3 Mutations in SCN2A have been reported in patients with DS, GEFS þ , benign familial