Abnormal protein levels and messenger RNA (mRNA) expression of cardiolipin synthase-1 (CLS-1), an essential enzyme for the synthesis of cardiolipin, and the CL remodeling enzymes tafazzin-1 and acyl-CoA:lysocardiolipin acyltransferase-1 (ALCAT-1) occur in LV myocardium of the failing heart and in cardiomyopathic hearts of patients with BTHS. The gene discussed is CRLS1; the disease is Barth syndrome.