应用变性高效液相色谱技术筛查一个正常血钾性周期性麻痹家系的SCN4A基因突变

目的 应用变性高效液相色谱(DHPLC)技术筛查一发生Met1592Val替换的正常血钾性周期性麻痹(normoKPP)家系的SCN4A基因,证实该突变为疾病相关突变,并总结其在此家系的临床表型特点。方法 总结一normoKPP家系14例患者的临床特点,应用DHPLC技术筛查SCN4A基因全部24个外显子,并对发现异常洗脱峰者进行测序。结果 该家系具有典型的normoKPP临床特征,无肌强直表现及早显、性别偏移现象,病程呈良性过程,发病早晚与症状严重程度及预后无相关。DHPLC筛查发现在外显子1及24存在杂合二倍体,测序及连锁分析证实位于外显子1的突变为良性多态性,外显子24的Met1592Val替换为疾病相关突变。结论 国人存在Met1592Val突变,此突变可导致normoKPP。normoKPP与高钾性周期性麻痹临床表现相似,两者可存在共同突变。

Screening SCN4A gene for mutations with denaturing high performance liquid chromatography technology in a Chinese family with normokalemic periodic paralysis

Objective To study the clinical features of normokalemic periodic paralysis (normoKPP) and to confirm the relation between Met1592Val mutation and normoKPP and clarify its clinical features. Methods The clinical features of 14 patients in a Chinese family of normoKPP were summarized. All 24 exons of SCN4A gene were screened with denaturing high performance liquid chromatography (DHPLC) technology, and then sequence analysis was performed on those with abnormal elution peak. Results This family showed typical clinical features of normoKPP without myotonia. The progress of most patients was benign. Two missence mutations were found in exon 1 and exon 24 respectively. Linkage analysis and direct sequencing showed the mutation in exon 1 was g189a, a benign polymorphism, and the mutation Met1592Val in exon 24 was responsible for this disease. Conclusion The mutation Met1592Val does exist in Chinese patients, and lead to normoKPP. NormoKPP is similar to hyperKPP not only in clinical futures but also in genetic level.