Central hypothyroidism.

A 15-mth-old male child of consanguineous parents, presented with classical features of congenital hypothyroidism. Serum total thyroxine (T4), total triiodothyronine (T3) and TSH were low. There was no evidence of deficiency of other pituitary hormones. Magnetic resonance imaging of the pituitary was normal. TSHB gene sequencing revealed a homozygous missense mutation due to single base substitution G?A at codon 85 resulting in change from Glycine to Arginine. This mutation in TSHB gene has been reported earlier in three cases with similar phenotype from Japan.