TAFAZZIN and congenital myopathy with cores: Moreover, reductions in CL 18:2n6 composition and CL content due to mutations in the tafazzin gene (Taz) is the primary defect underlying Barth syndrome - a rare congenital myopathy characterized by structural and functional mitochondrial abnormalities, cardio/skeletal myopathy, exercise intolerance and greater reactive oxygen species (ROS) production7, 11, 15–17.