Influence of SCN1A intronic mutations in mRNA splicing and relation of mRNA splicing changes with phenotype in febrile seizures related epilepsy / 中华神经医学杂志

ABSTRACT

Objective To study the influence of SCNIA intronic mutations in mRNA splicing in febrile seizures related epilepsy,and investigate the association between splicing changes and genotype-phenotype-inheritance pattern.Methods Molecular cloning of 5 SCN1A intronic mutations was performed in patients with partial epilepsy with antecedent febrile seizures plus (PEFS+) and Dravet syndrome (DS) through constructing mutant and wild-type plasmids of pTragetE2-3-4-5 and E24-25-26 by using Minigene splicing assay,and the in vitro expressions in HENK293 cells were detected.The mRNA splicing changes were analyzed qualitatively and quantitatively by reverse transcription (RT)-PCR and real time quantitative (q)-PCR.Results (1) Using RT-PCR,DS mutants presented a whole exon skipping without significant remain of normal mRNA transcripts,while PEFS+ mutants showed partial exon skipping or intronic insertion with coexistence of normal and aberrant mRNA transcripts.(2) Statistical differences were found between relative quantity (RQ) of aberrant and normal mRNA in PEFS+ mutant (c.473+5G＞A:4.92％±1.05％ and 6.10％±0.21％;c.473+5G＞C:7.97％±1.12％ and 3.94％ ±1.25％) and that in DS mutant (c.602+1G＞A:60.51％±1.81％ and 0.060％±0.022％,P＜0.05);similarly,there were statistical differences between relative RQ of normal and aberrant mRNA in PEFS+ mutant c.4853-25T＞A (71.22％±11.92％ and 7.38％±1.61％) and that in DS mutant c.4853-1G＞C (0.08％±0.01％ and 22.11％±2.83％,P＜0.05).Conclusion The position and difference of splicing patterns of SCNIA intronic mutations are potential molecular pathogenesis for phenotypic difference of febrile seizures related epilepsy.