Variants in the Gene Associated With Infantile Spasms.

The gene is related to a variety of diseases, including spinal muscular atrophy with lower extremity-predominant 1, Charcot-Marie-Tooth disease type 2O, and mental retardation, autosomal dominant13 (MRD13). Some patients with variant also had epilepsy. This study aimed to detect variants in Chinese patients with infantile spasms (ISs). We reviewed clinical information, video electroencephalogram (V-EEG), and neuroimaging of a newly identified cohort of five patients with gene variants. Five patients with four variants from four families were included. All patients had epileptic spasms (ESs), the median age at seizure onset was 7.5 months (range from 5 months to 2 years 7 months), and the interictal V-EEG results were hypsarrhythmia. Four of five patients had brain magnetic resonance imaging (MRI) abnormalities. Four variants were identified, including two novel variants (p.N1117K, p.M3405L) and two reported variants (p.R1962C, p.F1093S). As for the variant site, two variants are located in the tail domain, one variant is located in the motor domain, and one variant is located in the stalk domain. All patients had tried more than five kinds of antiepileptic drugs. One patient has been controlled well by vigabatrin (VGB) for 4 years, and another patient by VGB and steroids for 1.5 years. The other three patients still had frequent ESs. All patients had severe intellectual disability and development delays. IS was one of the phenotypes of variants. Most patients had non-specific brain MRI abnormality. Two of four variants were novel, expanding the variant spectrum. The IS phenotype was related to the variant's domains of variant sites. All patients were drug-refractory and showed development delays.