Mutation screening of SCN1A 3′ untranslated region on Dravet syndrome patients and functional analysis of the variant

Objective To conduct mutation screening of SCN1A 3′ untranslated region (UTR) on Dravet syndrome (DS) patients without mutations in the SCN1A coding region and promoter region, and functional analysis of the variant from DS patients . Methods Twenty-eight DS patients without mutations in the SCN1A coding region and promoter region were screened for SCN1A 3′ UTR mutations using PCR and direct sequencing. Functional analysis of the detected mutation was done via luciferase assay, mRNA stability analysis and RNA electrophoretic mobility shift assay (RNA-EMSA). Results A novo variant (c.*20A>G) in SCN1A 3′ UTR was found in one DS patient. The variant (c.*20A>G) reduced the luciferase gene expression by 30% through increasing the affinity of pluripotent embryonal carcinoma cell line NT2/cytoplasmic protein binding and reducing luciferase gene mRNA stability (t=8.5, P<0.01). Conclusions A functional variant was detected from one patient with DS. This variant negatively regulated the gene expression by increasing the affinity of pluripotent embryonal carcinoma cell line NT2/cytoplasmic protein binding and reducing mRNA stability. Key words: Dravet syndrome; Sodium channel; SCN1A gene; 3′ Untranslated region; Mutaiton