Homozygous PPP1R13L Mutation Associated with Dilated Cardiomyopathy in a 1-Year-Old Child.

Introduction: Dilated cardiomyopathy (DCM) is a relatively rare manifestation of pediatric heart failure. Despite recent diagnostic advancements and expanded screening modalities, the underlying cause of DCM remains elusive in over 50% of pediatric cases. We report the case of a 1-year-old girl presenting with newly diagnosed, rapidly progressive dilated cardiomyopathy, caused by a novel, rare homozygous pathogenic variant in the PPP1R13L gene. Case presentation: The patient, with no significant family history of cardiac disease, previously asymptomatic and in good health, presented with a 2-day history of nausea, vomiting, difficulty breathing, and low urine output, following a recent respiratory infection. The echocardiography identified a dilated left ventricle (Z score > +2 for age) and severe systolic left ventricular dysfunction, and a positive diagnosis of dilated cardiomyopathy was confirmed by the cardiac magnetic resonance (CMR). Genetic testing identified a homozygous pathogenic variant in the PPP1R13L gene, classified as a novel pathogenic variant that encodes the inhibitor of apoptosis-stimulating protein of p53 (iASPP). Despite targeted treatment, the severe systolic dysfunction persisted, and the general state progressively deteriorated and warranted the need for a cardiac transplant, which she underwent one year following the initial diagnosis. Conclusions: Patients diagnosed with underlying genetic DCM, particularly those harboring PPP1R13L mutations, carry an exceedingly poor prognosis in the absence of orthotopic heart transplantation. Existent case reports confirm that disruptions in this gene predictably yield highly aggressive, life-threatening cardiomyopathies.