Beta-ketothiolase deficiency is a disorder that prevents the body from breaking down break down isoleucine, a protein building block, and ketones, an important energy source during fasting or illness. This leads to a build-up of harmful substances in the body, causing the symptoms of the disease.
Symptoms usually appear before the age of two and include vomiting, trouble breathing, low energy, confusion, and sometimes seizures. These symptoms often happen suddenly during what’s called a “ketoacidotic attack,” which can be triggered by illness, fasting, or eating too much protein. If not treated with a special diet, these attacks can quickly lead to coma or death. Some children who survive these episodes may have developmental delays. There is no cure for beta-ketothiolase deficiency. Treatment involves a special diet that is low in proteins and high in fats, along with frequent meals to avoid fasting. Some people may need to take carnitine supplements. Close monitoring by a doctor is essential, especially during illness when symptoms like vomiting or fever require immediate attention.
This condition is caused by pathogenic (disease-causing) variants in the ACAT1 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance of having a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.
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Written August 2024
