Elevated TSH levels in a mentally retarded boy.
The Allan-Herndon-Dudley syndrome (AHDS;MIM 300523) of X-linked mental retardation and hypotonia is caused by mutations in a thyroid hormone transporter gene--the monocarboxylate transporter 8 (MCT8 also known as SLC16A2) gene. A 23-month-old boy with severe developmental delay, hypotonia, recurrent emesis, and irritability is described. He was diagnosed with hypothyroidism at the age of 4 months. However, T3 level was elevated. Molecular analysis of the MCT8 gene detected a single base duplication in exon 5 c.1614dupC (p.Ile539fs), consistent with a diagnosis of AHDS. While T3 is the best marker for this disorder, elevations in TSH should alert to the diagnosis.
Crushell
Ellen
E
National Centre for Inherited Metabolic Disorders, Children's University Hospital and Our Lady's Children's Hospital, Dublin, Ireland.
Reardon
William
W
D017353:Gene Deletion; D020440:Gene Duplication; D006801:Humans; D007037:Hypothyroidism; D007223:Infant; D008297:Male; D038901:X-Linked Intellectual Disability / Q000097:blood* / Q000175:diagnosis / Q000235:genetics; D027501:Monocarboxylic Acid Transporters / Q000235:genetics*; D009123:Muscle Hypotonia / Q000151:congenital; D013577:Syndrome; D013972:Thyrotropin / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood
D027501:Monocarboxylic Acid Transporters; D014284:Triiodothyronine; D013972:Thyrotropin