Swansea University 1 article published in JoVE Biochemistry Fingerprinting Cardiolipin in Leukocytes by Mass Spectrometry for a Rapid Diagnosis of Barth Syndrome Roberto Angelini*1, Silvia Russo*2, Angela Corcelli2, Simona Lobasso2 1Medical School, Swansea University, 2Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro This protocol shows how to obtain a mass spectrometric "fingerprint" of leukocyte cardiolipin for the diagnosis of Barth syndrome. The assessment of elevated monolysocardiolipin to cardiolipin ratio discriminates patients with Barth syndrome from control heart failure patients with 100% sensitivity and specificity.