Life Lines by Dr. Dolittle

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Drosophila help researchers understand rare genetic disorder

Barth syndrome consistent facial features of boys (Orphanet Journal of Rare Diseases Clarke et al).jpg

Image of young boys with Barth Syndrome from Wikimedia Commons. Photo Caption: Young boys with Barth syndrome have consistent facial features with a tall, broad forehead, round face with full cheeks, prominent ears and deep-set eyes. These features become less evident during puberty and into early adulthood, although the eyes may remain deep set and ears prominent.

Barth Syndrome is a rare genetic disorder that affects mainly males. It is characterized by impaired lipid metabolism, muscle weakness, growth delays, cardiomyopathy, and low numbers of neutrophils in the blood, which renders patients with the condition more susceptible to infections. There is no known cure for Barth Syndrome. In the past, patients with Barth syndrome often died by the age of three from infections or heart failure (Barth Syndrome Foundation). Of the patients that now survive into adulthood, many are living into their 40’s.   

The cause of Barth syndrome is a mutation in a gene called tafazzin (TAZ). This gene is important for the production of cardiolipin, a phospholipid that helps stabilize mitochondria and maintain normal mitochondrial function (Damschroder et akl., 2018). Changes in cardiolipin are also found in conditions like diabetes and heart failure (Houtkooper and Vaz 2008). Because of alterations in the mitochondria, patients with Barth Syndrome often experience muscle weakness and a general inability to conduct exercise, known as exercise intolerance.

In a new study published in Physiological Reports, researchers describe a drosophila model of Barth Syndrome. Like humans with Barth Syndrome, these mutant drosophila show signs of muscle weakness that worsens as the animals age. Even after an exercise training program, the drosophila remain unable to exercise. Unlike human patients, however, this animal model does not develop impaired cardiac function. For this reason, these mutant drosophila may be useful models in which to study exercise intolerance in the absence of impaired cardiac function.

Sources:

D Damschroder, C Reynolds, R Wessells. Drosophila tafazzin mutants have impaired exercise capacity. 

RH Houtkooper, FM Vaz. Cardiolipin, the heart of mitochondrial metabolism. Cell Mol Life Sci. 65(16):2493-2506, 2008. DOI: 10.1007/s00018-008-8030-5.

Categories: Comparative Physiology

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