Barth syndrome is a rare, sex-linked genetic disorder of lipid metabolism that affects males. Typically, boys with Barth syndrome present with hypotonia (low muscle tone) and dilated cardiomyopathy (labored breathing, poor appetite, and/or slow weight gain) at or within the first few months after birth. Other important features of Barth syndrome include bacterial infections because of neutropenia (a reduction in the number of white blood cells called neutrophils), muscle weakness, fatigue, and short stature. Although most children with Barth syndrome manifest all of these characteristics, some have only one or two of these abnormalities and, as a result, often are given incorrect diagnoses.

Barth syndrome occurs in many different ethnic groups and does not appear to be more common in any one group. To date, there are no good studies of the population or birth incidence of Barth syndrome, however probably fewer than 10 new Barth infants are identified each year in the United States, which suggests an incidence of only 1 in every 300,000 – 400,000 births. The gene for Barth syndrome, Tafazzin (TAZ), is located on the long arm of the X chromosome (Xq28). Mutations in the TAZ gene lead to decreased production of an enzyme required for the synthesis of “cardiolipin,” a special lipid that is important in energy metabolism. There is no specific treatment for Barth syndrome, but each of the individual problems can be successfully controlled, and both the heart disease and short stature often resolve entirely after puberty.