相同基因型而不同表现型的PRKAG2基因突变一家系报道

目的 位于7号染色体上的腺苷一磷酸激活的蛋白激酶γ^2调节亚单位基因（PRKAG2基因）调节代谢通路。报道一个具有PRKAG2基因突变而临床表现型不同的家系。方法 使用DNA直接测序法,对一个具有多种形式心律失常的患者家系（13例患者）进行PRKAG2外显子及外显子和内含子拼接部位序列筛查寻找基因突变。结果 心电图显示患者家系存在窦性心动过缓、短PR间期、完全性右束支传导阻滞、房室传导阻滞和房性心动过速。其中3例患者在年轻时发生猝死,没有1例有预激综合征（预激）表现,只有1例有心肌肥厚。DNA测序结果显示,该家系所有患者皆有一个PRKAG2错义突变（R302Q）。这个基因突变以前曾描述并与预激和左室肥厚有关。结论 PRKAG2基因突变不仅导致预激而且与多种临床表现型有关。完全性右束支传导阻滞、窦性心动过缓、短PR间期应该高度怀疑有PRKAG2基因突变的可能。

Same genotype and different phenotypes in a family with PRKAG2 gene mutation

OBJECTIVE: The gamma(2) subunit of AMP-activated protein kinase (PRKAG2) located in chromosome 7 plays an important role in regulating metabolic pathways, and patients with PRKAG2 mutations are associated with familial ventricular pre-excitation, hypertrophic cardiomyopathy and AV block. We observed the difference on the phenotypes in a large family with same PRKAG2 mutation. METHOD: Direct DNA sequence was performed to screen the exons and exon-intron boundaries of PRKAG2 gene in a large family with 13 affected persons detected by electrocardiography (ECG). RESULTS: Sinus bradycardia, short PR interval, right bundle bunch block (RBBB), complete AV block, atrial flutter, atrial fibrillation and sudden cardiac death were identified in this family. Hypertrophic cardiomyopathy was found in one family member. Genetic analysis revealed a missense mutation (Arg302Glu) in all affected family members. This mutation was previous described in patients with Wolff-Parkinson-White (WPW) syndrome and hypertrophic cardiomyopathy. CONCLUSIONS: Besides WPW syndrome and hypertrophic cardiomyopathy, PRKAG2 mutations are responsible also for a diverse phenotypes. PRKAG2 gene mutation should be suspected with familial occurrence of RBBB, sinus bradycardia, and short PR interval.