Genetic cardiomyopathy unmasked by pregnancy: X-linked dystrophinopathy presenting as peripartum cardiomyopathy-a case report.

Background: Peripartum cardiomyopathy (PPCM) is an uncommon cause of heart failure occurring towards the end of pregnancy or in the months following delivery. Although often considered idiopathic, emerging evidence suggests a significant genetic contribution in some patients. Case summary: We report a 31-year-old woman who presented 10 weeks postpartum with symptoms of advanced heart failure. Transthoracic echocardiography revealed a severely reduced left ventricular ejection fraction (18%). Cardiac magnetic resonance imaging confirmed severe systolic dysfunction with non-ischaemic late gadolinium enhancement. After exclusion of other causes, PPCM was diagnosed. She was initiated on guideline-directed heart failure therapy and bromocriptine for lactation suppression. As part of the ongoing evaluation, endomyocardial biopsy revealed persistence of parvovirus B19 without histological evidence of active myocarditis. Genetic testing was initiated, and results later identified a pathogenic X-linked deletion of exons 44-50 in the dystrophin (DMD) gene, consistent with cardiac-restricted dystrophinopathy. The patient has remained clinically stable under ongoing therapy. Discussion: This case underscores the importance of considering genetic testing in PPCM. The identification of an X-linked dystrophin gene deletion was unexpected, as the patient had no neuromuscular symptoms. Such mutations may manifest as isolated cardiomyopathy in female carriers, with pregnancy serving as a precipitating physiological stressor. Identifying a genetic cause enables optimized management and facilitates targeted family screening.