PRKAG2 Syndrome Presenting With Fetal Sinus Bradycardia and Pulmonary Valve Stenosis as Initial Manifestations.

This report describes a novel prenatal presentation of PRKAG2 syndrome in a female. Delivered at 37 weeks, she had severe pulmonary valve stenosis, successfully treated with balloon dilation at one month. Early childhood featured persistent, asymptomatic sinus bradycardia and sinus node dysfunction, followed by childhood-onset epilepsy. By age 8, she developed symptomatic bradycardia. Echocardiography revealed ventricular hypertrophy, and whole exome sequencing identified a heterozygous PRKAG2 variant (c.1642T >C). This case expands the phenotype of PRKAG2 syndrome, uniquely combining congenital pulmonary stenosis with progressive conduction disease and epilepsy, distinct from severe fetal cardiomyopathy or Noonan syndrome.