Differing clinical courses and outcomes in two siblings with Barth syndrome and left ventricular noncompaction

Barth syndrome is an X-linked disorder usually diagnosed in infancy. It is characterized by hypotonia, dilated cardiomyopathy, neutropenia, growth retardation, and 3-methylglutaconic aciduria. The syndrome is typically caused by mutations in the TAZ (G4.5) gene, which encodes a novel protein family called the tafazzins. We report the case of two brothers with Barth syndrome and left ventricular noncompaction (LVNC) caused by a splice donor mutation in TAZ. Both had impaired sucking ability at the age of 2 months. The elder brother was diagnosed with LVNC at the age of 4 months; by that time he had developed severe heart failure with metabolic decompensation. He died at 12 months of age due to intractable heart failure despite pharmacological therapy with diuretics, an angiotensin-converting enzyme inhibitor, and a beta-blocker. However, the younger brother, who was diagnosed as having Barth syndrome and LVNC with heart failure at the age of 2 months, received early medical treatment and demonstrated normal echocardiographic findings.

The clinical courses of Barth syndrome observed in our cases show the phonotypic variability of this syndrome and suggest that early therapy may be beneficial for maintaining cardiac function.