Abstract: The present disclosure is directed to methods of treating Allan-Herndon-Dudley syndrome comprising administering 3,5-diiodothyropropionic acid (DITPA) to a pregnant mother of a prenatal subject in need thereof, and to pharmaceutical DIPTA formulations for administration to the pregnant mother of a prenatal subject in need thereof.

Abstract: The present subject matter is directed to methods of treating Allan-Herndon-Dudley syndrome comprising administering 3,5-diiodothyropropionic acid (DITPA) to a subject in need thereof, wherein the DITPA administration reduces triiodothyronine (“T3”) serum levels to normal, increases T3 brain levels to normal, and maintains normal serum levels of thyroxine (T4) and thyroid stimulating hormone (TSH). The subject may be a child or an adult.

Abstract: The present disclosure is directed to methods of treating Allan-Herndon-Dudley syndrome comprising administering 3,5-diiodothyropropionic acid (DITPA) to a subject in need thereof, and to administering gene therapy to the subject by introducing normal human MCT8 into the subject's cells in order to increase T3 in the subject's brain.