Barth syndrome is mainly found in early infancy or childhood. However, in some patients, symptoms appear in adulthood. Symptoms can present differently and can vary from one person to another.
Males with Barth syndrome could have various heart problems like dilated cardiomyopathy, hypertrophic cardiomyopathy, endocardial fibroelastosis and left ventricular non-compaction. Dilated cardiomyopathy is when the left ventricle muscle becomes enlarged and weak which decreases the heart’s ability to pump blood. In some people with Barth syndrome, the heart muscles become very thick making it difficult to pump blood (hypertrophic cardiomyopathy). Sometimes, this thickening may be due to the build-up of connective tissues and elastin fibres (endocardial fibroelastosis). In other patients, the left ventricles do not develop properly (left ventricular noncompaction) so instead of the muscle being smooth, it becomes thick and spongy making it difficult to pump blood. These heart findings are almost always present before the age of 5. Sometimes the heart problems can be seen on an ultrasound exam in the last trimester in pregnancy. In addition to structural differences to the heart, in some adolescents and young adults, there could be an Irregular heartbeat identified (arrhythmia). The heart problems might lead to decrease in blood circulation from in the body and to the lungs (heart failure). Symptoms of heart failure may include Shortness of breath, tiredness and Nausea, but the symptoms depend on the child and other factors.
People with Barth syndrome have a low level of white blood cells (neutropenia). The white blood cells in our body help us fight infections. Due to neutropenia, people have mouth ulcers, pneumonia or blood infections. Males with Barth syndrome have weak muscles (hypotonia) especially in the hands and feet. Due to the hypotonia, children take longer to develop gross motor skills like crawling, sitting or walking. Due to the heart issues and weak muscles, these boys do not tolerate exercise well. Males with the condition have growth delay during childhood, but there is a significant growth spurt in puberty. Other symptoms include curvature of the spine (scoliosis) and delayed bone age.
Males with Barth syndrome have distinct facial features. They have a round face with prominent chin and full cheeks. The ears are large, and they have deep set eyes. The facial features become less noticeable with age. The striking feature in adolescence and adulthood is the fat distribution in the hips, thighs and chest.
People diagnosed with the condition have some form of learning disability. They have age appropriate reading skills and vocabulary. However, they may need extra help with mathematics. Their first words or forming sentences can be delayed in comparison to other people. They have delay in developing skills like reading a map, recognizing shapes and finding objects in a picture. The boys have feeding difficulties. The Barth syndrome registry data suggest that a third of males with this condition would need a tube put through the nose or directly to the stomach for feeding. Boys with this condition are picky eaters. Salty, cheesy and spicy food are some of the foods they prefer.
In addition to the cardiomyopathy, neutropenia and growth delay, people with this condition have increased levels of biochemical markers. Increased levels of 3-methyglutaconic acid and 2-ethyl hydracrylic acid in the urine or blood is the common marker used to reach a diagnosis. However, there have been no symptoms associated with the increased levels of these chemicals.