A newly discovered genetic condition called TMLHE deficiency results in the loss of the ability to make carnitine in the body¹. Arthur Beaudet and his colleagues at Baylor College of Medicine in Houston, Texas, hypothesize that carnitine deficiency in the brain can cause autism, and that dietary supplementation with carnitine may prevent or reverse autism symptoms associated with TMLHE deficiency².

Carnitine is a dietary nutrient found mainly in red meats, but it is also synthesized in the brain, liver and kidney. The condition was discovered in boys with autism, but it is also common in healthy adult males.

The trimethyllysine hydroxylase epsilon, or TMLHE, gene is on the X chromosome, so the deficiency is sex-linked and occurs predominantly in males. TMLHE deficiency is 2.82 times more frequent in brother-brother pairs with autism compared with control pairs and occurs in up to one percent of people with autism. Further studies are needed to confirm the link to autism because many healthy males also have the deficiency.]

Beaudet and his colleagues plan to carry out a clinical trial of carnitine administration in young boys with autism and TMLHE deficiency to test whether carnitine supplementation can reverse the symptoms of autism. They also plan to assess whether carnitine supplements can prevent or reverse symptoms of autism in people without TMLHE deficiency.