Infantile dilated cardiomyopathy caused by RPL3L gene mutation: A case report.

Ribosomal protein L3-like gene mutations have been implicated in early-onset severe dilated cardiomyopathy (OMIM #115200). This report describes an infant with dilated cardiomyopathy resulting from RPL3L gene mutations. A 2-month-old girl was admitted in June 2022 with poor appetite, breathlessness, and lethargy. Her brother had succumbed to fulminant cardiomyopathy and heart failure at the same age. Cardiac ultrasound revealed an enlarged left ventricle, moderate mitral valve regurgitation, and an ejection fraction of 31%. Chest X-ray revealed cardiac enlargement and pulmonary changes. Cardiac magnetic resonance imaging confirmed dilated cardiomyopathy with an enlarged left ventricle and reduced myocardial wall motion. Whole-exome sequencing identified two RPL3L mutations: c.501G>A (p.Q167=) inherited from the father and c.322G>A (p.E108K) from the mother. Drug therapy improved the patient's cardiac function, and she demonstrated normal cardiac function after 6 months. In this case, dilated cardiomyopathy was associated with two familial RPL3L gene mutations, consistent with a presumed autosomal recessive inheritance pattern previously described in RPL3L-associated cardiomyopathy.