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

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.

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).

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.

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.