ESPE Abstracts

Introduction: Allan–Herndon–Dudley syndrome is a rare X-linked inherited disorder characterized by, axial hypotonia, weakness, and severe intellectual disability¹ Allan-Herndon-Dudley syndrome is caused by mutations in the SLC16A2 gene (also known as MCT8) This gene is located on the chromosome Xq13.2, mutations of the SLC16A2 gene lead to impaired making a protein that transports thyroid hormone triiodothyronine (T3) into nerve cells, for this reason due to T3 accumulation in the blood, development of the nervous system is disrupted thus mental retardation, and delay of developmental milestones will be happened. Diagnosis is suspected by combination of clinical examination and thyroid profile tests; normal TSH, elevated free T3 and decreased free T4 in the blood and confirmed by molecular genetic testing. In this report, a 3, 5 year old boy with AHDS is presented in whom SLC16A2 gene mutation was detected. To our best knowledge, this is the first report of disease in an Iranian child with AHDS.