Barth syndrome is a rare but serious genetic disorder that primarily affects males. It is caused by a mutation on the X chromosome, making it an X-linked disorder. The mutation in the gene leads to a decreased or stop of the production to produce certain lipids which are important in metabolism. It is believed that Barth syndrome is underdiagnosed and is estimated to occur in roughly 1 out of 300,000 people.
Signs and Symptoms
Barth syndrome affects many systems making this disorder severe. Affected individuals have varying levels of cardiomyopathy, a disorder of the heart muscle that decreases heart functioning and activity. People with cardiomyopathy are at risk of sudden heart attack, arrhythmia or both. Some patients experience a decrease of white blood cells which can increase the risk for bacterial infections, reduced muscle tone, delayed and undeveloped growth.
At the cellular level, the mitochrondia that support the cells with power can be damaged or ineffective. Because of this, the cell loses the ability to break down certain organic acids that instead build up in the urine.
Other symptoms include physical disability, lack of stamina, and muscle weakness.
Like all genetic disorders, a mutation in an essential gene is at fault for the onset. In this case, a mutation in the gene TAZ is responsible. TAZ produces an enzyme that produces cardiolipin, which is housed in the inner mitochrondrial membrane and essential in metabolism. It has an important role in the electron transport chain and membrane structure of mitochondria. Cardiolipid is also found in large quantities of the heart and was first isolated from beef heart in the 1940s.
TAZ is located on the X chromosome. When inherited, males have a higher chance of risk because of their XY genotype. Females, however have XX and thus a lower chance of contracting the disorder. Females who have one affected X and one unaffected X do not show signs of Barth Syndrome.
Diagnosis and Treatment Options
Diagnosis of Barth syndrome is primarily phenotype, or by what is or is not expressed. Once the patient starts to display the characteristic signs and symptoms, a genetic sequencing of the X chromosome can be completed. This will confirm that the patient has Barth syndrome and begin any treatment options.
There is no cure or treatment for Barth syndrome, however, there are other options to combat infection and heart failure. Antibiotics can help fight off bacterial infections and medicines can be used to increase white blood cell count. Additional medications can be used to increase heart and muscle function.
Early diagnosis of Barth symdrome is imperative. Even though no cure exists, medicines can prolong life.