Two novel PCDH19 mutations in Russian patients with epilepsy with intellectual disability limited to females: a case report

摘要

Epilepsy with intellectual disability limited to females (Epileptic encephalopathy, early infantile, 9; EIEE9) is a rare early infantile epileptic encephalopathy characterized by an unusual X-linked inheritance: females with heterozygous mutations are affected, while hemizygous males are not. We describe the clinical and molecular characteristics of 2 Russian patients with EIEE9 (females, ages 3?years and 7?years). In these patients seizures developed at the age of 3?years. Additionally, for our patients and for cases described in the literature we searched for a possible relationship between the type and localization of the mutation and the EIEE9 clinical phenotype. We identified two novel PCDH19 mutations in EIEE9 patients: a missense mutation in exon 1 (c.1236C??A, p.Asp412Glu) and a frameshift in exon 3 (c.2386_2387insGTCT, p.Thr796fs). We conclude that the age of seizure onset and the presence of intellectual disability may depend not on the type and localization of PCDH19 mutations, but on the X-inactivation status. The study also highlights the need to screen for EIEE9 among young female epilepsy patients.