CAUSES
Although pediatric cardiomyopathy is one of the leading causes of cardiac death in children, an explanation for why it occurs remains unknown. Most cases are familial conditions that are genetically transmitted, but the disease can also be acquired during childhood. The most common cause for acquired cardiomyopathy is myocarditis, a viral infection that weakens the heart muscle. Other causes for acquired cardiomyopathy include: 1) cardiovascular conditions (i.e. Kawasaki disease, congenital heart defect, hypertension, cardiac transplantation or surgery), 2) infectious or inflammatory diseases, 3) immunologic diseases (i.e. HIV), 4) obesity or dietary deficiencies, 5) toxin reactions (i.e. drug, alcohol, radiation exposure), 6) connective tissue and autoimmune diseases, 7) endocrine diseases and 8) pregnancy related complications. Persistent rhythm problems or problems of the coronary arteries, either congenital or acquired, can also lead to a weakening of the heart.
It is being increasingly recognized that certain genetic mutations are the primary cause for pediatric cardiomyopathy. Mutations are defects in the DNA spiral, the protein structure of many genes. The abnormalities in DNA involve a displacement in the sequence of one or more of the amino acids that make up a gene protein. The disease is either inherited through one parent who is a carrier (autosomal dominant transmission with a 50% chance of recurrence) or through both parents who each contribute a defective gene (autosomal recessive transmission with a 25% chance of recurrence). Cardiomyopathy can also be inherited by maternal transmission (X-linked). Research continues to focus on identifying the specific genes that cause cardiomyopathy and better understanding how these genetic abnormalities contribute to the disease. However, it is a complex process with multiple diverse genes producing extremely variable outcomes.