MCT8 mutations cause an X-linked syndromic disorder known as Allan-Herndon-Dudley syndrome (AHDS) that is characterized by severe psychomotor delays, abnormal thyroid function, and hypomyelinated leukodystrophies.
We report mutations in the thyroid hormone transporter gene MCT8 in 11% of 53 families affected by hypomyelinating leukodystrophies of unknown aetiology.