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Genetic and Rare Diseases Information Center (GARD)

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Barth syndrome

Other Names for this Disease
  • 3-methylglutaconic aciduria type II
  • BTHS
  • Cardioskeletal myopathy with neutropenia and abnormal mitochondria
  • MGA type II
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What are the signs and symptoms of Barth syndrome?

Symptoms associated with Barth syndrome may be evident at birth, infancy, or early childhood. Rarely, the disorder may not be diagnosed until adulthood. Most individuals with Barth syndrome present with weakened heart muscle (cardiomyopathy) that leads to the enlargement of the heart's lower chambers (ventricles). Known as dilated cardiomyopathy, signs of this condition are often present at birth, or may appear during the first months of life. Dilated endocardial myopathy typically weakens the heart's pumping action, reducing the volume of blood circulating to the lungs and the rest of the body (heart failure). Symptoms of heart failure may depend on the child's age and other factors. In young children, for example, heart failure may be manifest as fatigue and shortness of breath with exertion.[1]

Barth syndrome is also associated with abnormally diminished muscle tone (hypotonia), and muscle weakness (skeletal myopathy), that often leads to delays in development of gross motor skills. Gross motor skills include such activities as crawling, walking, running, jumping, and maintaining balance. Weakness of the facial muscles may lead to unusual facial expressions. In addition, affected infants and children may fail to thrive, and fail to gain weight at the expected rate. Some affected children have mild learning disabilities (although they are usually of normal intelligence), and in many cases, may be prone to recurrent bacterial infections due to low levels of circulating neutrophils in the blood (neutropenia).[1]

In addition to the signs and symptoms previously mentioned, individuals with Barth syndrome have abnormally increased levels of a substance called 3-methylglutaconic acid in their urine and blood. However, there does not appear to be an association between the increased acid levels and the severity of other symptoms and signs associated with Barth syndrome.[1]
Last updated: 6/3/2011

  1. Barth Syndrome. NORD. September 17, 2007; Accessed 6/3/2011.