Barth syndrome (BTHS) is a rare, X-linked genetic disease estimated to occur in 1 in 1 million male live births.1 Barth syndrome pathophysiology involves abnormal cardiolipin, an inner mitochondrial membrane phospholipid critical to mitochondrial function, that occurs due to mutations in the TAFAZZIN gene encoding an acyltransferase necessary for the remodelling and maturation of cardiolipin.2 Cardiomyopathy, the most common clinical manifestation of BTHS, occurs in ∼90% of patients (70% diagnosed in infancy/12% requiring cardiac transplantation at a median age of 1.7 years).3,4. Here, TAFAZZIN is linked to Barth syndrome.