Nemaline myopathy with dilated cardiomyopathy and severe heart failure: A case report

Nemaline myopathy (NM) is a rare type of congenital myopathy, with an incidence of 1:50000. Patients with NM often exhibit hypomyotonia and varying degrees of muscle weakness. Skeletal muscles are always affected by this disease, while myocardial involvement is uncommon. However, with improvements in genetic testing technology, it has been found that NM with a mutation in the myopalladin (MYPN) gene not only causes slow, progressive muscle weakness but also results in dilated or hypertrophic cardiomyopathy.

A 3-year-old pre-school boy was admitted to our hospital with cough, edema, tachypnea, and an increased heart rate. The patient was clinically diagnosed with severe dilated cardiomyopathy and heart failure, and subsequent gene examination confirmed the diagnosis of NM with a mutation in MYPN. Captopril, diuretics, low-dose digoxin, and dobutamine were administered. After 22 d of hospitalization, the patient was discharged due to the improvement of clinical symptoms. During the follow-up period, the patient died of refractory heart failure.

Decreased muscular tone and dilated cardiomyopathy are common features of MYPN-mutated NM. Heart transplantation may be a solution to this type of cardiomyopathy.