Skip to content
left end
left end
right end

Testing

Information on Testing for Barth Syndrome

Testing for Barth syndrome in the past has so far mostly been restricted to boys with dilated cardiomyopathy (DCM) AND neutropenia AND excessive amounts of 3-methylglutaconic acid in their urine. However, it is increasingly clear that the disease can behave very differently between affected males. As just two examples: 10% of boys do NOT have low blood neutrophil counts and it is well recognised that the level of 3-methylglutaconic acid can sometimes be normal in urine.

Previously, definitive testing for Barth Syndrome relied on sequencing of the responsible TAZ gene, but this is expensive and time-consuming. A more practical approach to testing  is now possible since  the development of a biochemical "cardiolipin test" which can be performed very  reliably on only a small volume of blood. The test result is usually available within one to two weeks and this is a more straightforward test than DNA sequencing (although gene testing would usually still be performed as further confirmation in someone with a positive cardiolipin test). When done on blood samples sent by first class post, cardiolipin testing discriminates extremely well between normal boys and those with Barth Syndrome.

It has been estimated that between 3 and 5% of all young males with DCM may have Barth Syndrome as the cause of their heart failure. This percentage may be even higher in those who are in heart failure at birth or develop it within the first year of life. We therefore recommend routine cardiolipin testing in all young males with dilated cardiomyopathy (DCM). Cardiolipin testing should also be considered in male babies/boys with left ventricular noncompaction (LVNC), unexplained neutropenia (especially with poor growth, developmental delay or weak muscles and easy fatigue) and in families with a male pattern of hypertrophic cardiomyopathy (HCM) but where no genetic cause can be found and other features suggestive of Barth Syndrome are present.
 

Routine blood testing: Cardiolipin Analysis

Cardiolipin analysis is temporarily unavailable in the UK.  The laboratory at Bristol Royal Infirmary continues however to facilitate testing for Barth syndrome by forwarding samples to the Academic Medical Centre (AMC) in Amsterdam for analysis.  Analysis of samples sent via the Bristol laboratory to the AMC are free of charge. 

Please take 1-3 ml of whole blood collected into a K-EDTA (full blood count) tube, Monday to Thursday only and send within 24 hours of collection by first class post to the:

Metabolic, Neuroendocrine and Nutrition Laboratory
Department of Clinical Biochemistry
Bristol Royal Infirmary
Bristol
BS2 8HW

Please label the box 'Urgent clinical sample - for immediate delivery to the Metabolic, Neuroendocrine and Nutrition Laboratory'. 

Alternatively a blood spot can be sent directly to The Academic Medical Centre (AMC), Amsterdam (see https://www.amc.nl/web/Het-AMC/Afdelingen/Medische-afdelingen/Laboratory-Genetic-Metabolic-Diseases-1/Cardiolipins.htm). 
Please note that samples sent directly to the AMC will incur a charge.

 

Post mortem testing

If a patient is suspected to have died as a result of Barth Syndrome, cardiolipin analysis can be performed in cultured fibroblasts (skin cells).  If fibroblasts are unavailable, please contact Vicki Powers to discuss details on 0117 342 2590 or by email at: victoria.powers@UHBristol.nhs.uk

Genetic testing by TAZ Gene Sequencing

Further information on genetic testing in Bristol, and a proforma for referral of samples are given here.