Barth Syndrome

Definition of Barth Syndrome

Barth syndrome (BTHS) is a rare disorder that is genetically inherited by an affected individual and usually occurs in males. The condition is commonly passed on from the mother to her son.

The mother herself who is the carrier of Barth syndrome does not experience any signs and symptoms certainly because of the skewed X-chromosome that had been inactivated.

There is about 50% chances that a baby boy born to a female who carries the syndrome will obtain the disorder, while females born to a carrier have approximately 50% chance of being carriers themselves. In the case of a male who has Barth syndrome, all of his daughters will be carriers while his sons will not be affected.

Since there are proofs that some mothers do not carry the disease, it is recommended that all mothers of children with Barth syndrome must undergo an examination in order to weigh the possibility of genetic risk in the family. Although the condition usually presents in times of early childhood or infancy, the specific age of onset, findings and symptoms, and the progression greatly depends even to those affected individuals of the same family.

Symptoms of Barth Syndrome

Symptoms of Barth syndrome may be noticeable at infancy, birth, or early childhood but on some very rare circumstances, the condition might not be recognized until adulthood.

Possible symptoms may include:

• Cardiomyopathy or the weakening of the heart muscles
• Weak or slowed muscle tone development
• Bacterial infections that often occur like pneumonia
• Levels of white blood cells are lowered leading to a condition known as neutropenia
• Certain abnormalities of the skeletal muscle
• Heart failures such as fatigue or shortness of breath
• Moderate learning disabilities
• Failure to normally gain enough weight

Pathology of Barth syndrome

The mutations in the TAZ gene are the cause of Barth Syndrome. This gene issue instructions for the protein production called tafazzin located in mitochondria structures, which are the energy-producing areas of cells. The involvement of tafazzin in making alterations of a fat known as cardiolipin is very essential since it plays an important role in the mitochondrial inner membrane. The changes made by tafazzin serve as the key for cardiolipin in sustaining production of energy, mitochondrial shape, and protein transport in the cells.

Mutations of TAZ gene lead to the tafazzin protein productions with small amount of function or nothing at all. As a result, there will be no cardiolipin alterations that can be done by tafazzin. If cardiolipin lacks function, the normal shape of the mitochondria is impaired.

Tissues that contain high energy demands like the skeletal muscles and the heart are most prone to cell death because of the decreased production of energy in mitochondria. In addition to that, some abnormal shaped mitochondria are sited in affected white blood cells that can possibly influence their capacity to mature and grow, resulting to neutropenia.

Treatment of Barth syndrome

There is no specific treatment available for Barth syndrome. The treatment options are mainly directed to specific symptoms that are present in each patient. Some supportive treatment cannot be done by the patient alone, but with the help of medical team professionals.

Treatment may include:

Antibiotics – They are medications that could be effective in treating bacterial infections such as neutropenia.

GCSF or granulocyte colony stimulating factor – It is a type of drug that could raise the production of white blood cells by the bone marrow and help fight off infections.

Medications – Specific medications may be prescribed by the physician to control heart problems.

Carnitine substance – It helps the body alter fat into energy. The dietary supplement has helped some children with the condition but in other cases it had caused an increased weakening of the muscles and sometimes leads to precipitated heart failure. A nutritionist or physician must be the only one that could carefully monitor the patient’s diet in order to have proper nutritional and caloric intake.

Prognosis of Barth syndrome

A precise and early diagnosis is the main key to prolong survival for individuals with Barth syndrome. The presence of acute cardiac failures and infections are the typical causes of death in children who are affected.

Life Expectancy

For several years of observation, life expectancy for Barth syndrome patients was generally low. A lot of them die in their early 20s or at times of puberty. Males who have the condition have a decreased life expectancy. Numerous cases of children who are affected die of infections or heart failures at a young age, but those who survive into adulthood could live into their late 40s.

References:

1. http://ghr.nlm.nih.gov/condition/barth-syndrome
2. Barth Syndrome – National Organization for Rare Disorders at https://rarediseases.org/rare-diseases/barth-syndrome/
3. Barth Syndrome – Treatment, Prognosis, Research, Organizations at http://www.brainfacts.org/diseases-disorders/diseases-a-to-z-from-ninds/barth-syndrome/
4. Steward CG, Newbury-Ecob RA, Hastings R; et al. (October 2010). “Barth syndrome: an X-linked cause of fetal cardiomyopathy and stillbirth”. Prenat. Diagn. 30 (10): 970–6.
5. Claypool SM, Boontheung P, McCaffery JM, Loo JA, Koehler CM (December 2008). “The cardiolipin transacylase, tafazzin, associates with two distinct respiratory components providing insight into Barth syndrome”. Mol. Biol. Cell 19 (12): 5143–55.
6. Kulik W, van Lenthe H, Stet FS; et al. (February 2008). “Bloodspot assay using HPLC-tandem mass spectrometry for detection of Barth syndrome”. Clinical Chemistry 54 (2): 371–8.