Conduction disorders as an early marker of cardiac glycogenosis (PRKAG2 syndrome)

The article presents a clinical case of familial PRKAG2-cardiomyopathy, illustrating diagnostic challenges and the importance of molecular genetic verification. A comprehensive clinical and instrumental examination of the proband and close relatives was performed, along with whole-exome sequencing. The proband, with a family history of sudden cardiac death, was found to have apical hypertrophy of the left ventricle, a history of supraventricular extrasystole, and atrial fibrillation. Her younger son was documented to have ventricular pre-excitation syndrome, bradycardia, and syncopal episodes. Genetic analysis identified a heterozygous pathogenic variant c.905G>A (p.Arg302Gln; rs121908987) in the PRKAG2 gene in both the proband and her younger son. The described case emphasizes that cardiomyopathy associated with the p.Arg302Gln variant can present with moderate myocardial hypertrophy, while electrophysiological disturbances (pre-excitation, bradyarrhythmias) and a burdened family history of sudden death take precedence in the clinical picture. Thus, the combination of conduction disorders (especially WPW syndrome) with mild hypertrophy and familial cases of sudden death forms a characteristic «red flag» for this disease. The presence of such a combination of signs in the family history necessitates targeted genetic testing for diagnosis verification and correct risk stratification.

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