家族性低钾性周期性麻痹存在SCN4A基因R672H突变

目的筛查低钾性周期性麻痹相关基因突变位点,总结该病基因型和临床表型的相关性。方法应用PCR和DNA测序技术,对2个低钾性周期性麻痹家系进行候选基因CACNA1S和SCN4A的筛查,并总结患者的临床特点。结果DNA测序发现2个家系5例患者在SCN4A基因12外显子上存在2015G→A突变引起R672H改变。家系A另外4人也携带此突变但未发病,其中3例女性,1例男性。家系B先证者母亲存在相同突变。R672H突变特征：钾剂治疗有效,乙酰唑胺治疗无效;外显率不全,女性突变基因携带者均未发病。结论中国家族性低钾性周期性麻痹存在SCN4A基因R672H突变。

The mutation R672H in SCN4A gene exists in Chinese patients with hypokalaemic periodic paralysis

OBJECTIVE: Mutation screening was performed on two Chinese families with HOKPP to locat the corresponding mutations and to specify the clinical features associated with the mutation. METHODS: Target-exon PCR and direct sequencing were used to screen mutation in the CACNA1S and SCN4A gene of all numbers of the two families. The clinical features of patients were summary. RESULTS: A heterozygous point mutation 2015G-->A causing R672H in the SCN4A was found in five patients and five normal relatives of the two families. Features of R672H mutation are incomplete penetrance, especially non-penetrance of phenotype in women and potassium is effective, but acetazolamide is not. CONCLUSION: The SCN4A R672H mutation exists in the Chinese family with HOKPP.