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目的 通过检测相关基因的突变位点来研究低钾性周期性麻痹 (HOKPP)这一常染色体显性遗传疾病的遗传学病因。方法 运用PCR扩增及反应产物直接测序的方法 ,对一个中国人低钾周麻家系 3 2名成员进行基因筛查 ,并运用亚克隆方法进行证实。结果 在编码Na通道的基因SCN 4A上第 2 0 14位核苷酸存在一个新点突变 (CGT TGT) ,为杂合突变 ,并引起相应编码氨基酸的改变 ,由原来的精氨酸变为半胱氨酸 (R672C) ,此突变为HOKPP一个新的突变类型 ,并且经亚克隆的方法进一步证实了此杂合突变。结论 在一中国人HOKPP家系的SCN4A 12号外显子上发现了新的点突变 (C2 0 14T ) ,它只在HOKPP患者中存在。家系中各患者的表现各不相同 ,提示了R672C突变型可能具有不完全外显的特性。
Objective To investigate the genetic etiology of hypokalemic periodic paralysis (HOKPP), an autosomal dominant disease, by detecting the mutation sites of related genes. Methods A total of 32 Chinese members of the low-potassium week-old Chinese family were genotyped by PCR amplification and direct sequencing of the reaction products. The subcloning method was used to confirm the results. As a result, a new point mutation (CGT TGT) was found on the SCN 4A gene encoding Na channel, which was a heterozygous mutation and caused a corresponding change in the encoded amino acid from the original arginine to a half Cystine (R672C), a mutation of which is a new mutation type of HOKPP, and this heterozygous mutation is further confirmed by subcloning. Conclusions A new point mutation (C2 0 14T) was found in SCN4A exon 12 of a Chinese HOKPP pedigree, which is present only in HOKPP patients. The performance of each patient in the family varies, suggesting that the R672C mutant may have incompletely characterized features.