While cardiomyopathy can be life-threatening, it is commonly resolved or substantially improved in Barth Syndrome patients after puberty.Neutropenia, a granulocyte disorder that results in a low production of neutrophils, the bodys primary defenders against bacterial infections, is another severe manifestation of Barth Syndrome. In general, lower levels of neutrophils render a patient more vulnerable to bacterial infections; in Barth Syndrome patients, however, there are reports of relatively fewer bacterial infections as compared to non-Barth patients with neutropenia. Cause
The tafazzin gene (TAZ, also called G4.5 or NG_009634) is highly expressed in cardiac and skeletal muscle; its gene product, Taz1p, functions as an acyltransferase in complex lipid metabolism. Any type of mutation of TAZ (missense, nonsense, deletion, frameshift, and/or splicing) is closely associated with Barth syndrome.In 2008, Dr. Kulik found that every patient with Barth Syndrome that he tested had abnormalities in their cardiolipin, a lipid found inside the mitochondria of cells. Cardiolipin is intimately connected with the electron transport chain proteins and the membrane structure of the mitochondrion, the energy-producing organelle of the cell. iPLA2-VIA has been suggested as a target for treatment.The human tafazzin gene is over 10,000 base pairs in length, the full-length mRNA, NM_000116, being 1919 nucleotides long, encoding 11 exons with a predicted protein length of 292 amino acids and a molecular weight of 33.5 kDa. It is located at Xq28; the long arm of the X chromosome. This explains the X-linked nature of Barth Syndrome. There are some case reports of women who are asymptomatic carriers of the TAZ mutation.
Any of their children might inherit the modified gene with a 50% probability, with the males developing Barth Syndrome and the females going on to be carriers themselves. Thus, it is vitally important to take familial histories of Barth Syndrome patients in order to determine genetic risk. Ideally, any male who is matrilineally related to an individual with Barth Syndrome should be tested for TAZ mutation(s). Because the phenotype can vary widely, even among affected siblings, symptomatology (or lack thereof) by itself is insufficient for diagnosis. Diagnosis
Early diagnosis of the syndrome is complicated, but of critical importance. Clinical presentation in Barth Syndrome is highly variable, with the only common denominator being early-onset and pronounced cardiomyopathy. Diagnosis is established based upon several tests, among which can be blood tests (neutropenia, white blood cell count), urinalysis (increased urinary organic acid levels), echocardiography (cardiac ultrasound, to assess (and detect abnormalities in) the hearts structure, function and condition), and, with reasonable suspicion of Barth Syndrome, DNA sequencing (to verify TAZ gene status). Differential diagnosis
Based on symptoms at time of presentation, the differential diagnosis may include other hereditary and/or nutritional causes of (dilated) cardiomyopathy and (cyclic or idiopathic) neutropenia. Treatment
Currently, there is no treatment for Barth syndrome, although some of the symptoms can be successfully managed. Clinical trials for possible treatments are ongoing, and preliminary research into AAV9-mediated TAZ gene replacement by the University of Florida has been promising.