A familial case of congenital hypothyroidism caused by a homozygous mutation of the thyrotropin receptor gene

Most of the time congenital hypothyroidism appears as a sporadic disease. I n addition to the rare defects in hormonosynthesis associated with goiters, the causes of congenital hypothyroidism include agenesis and ectopy of the thyroid gland. The study of some familial cases has allowed the identifica tion of a few genes responsible for congenital hypothyroidism. We report he re a familial case of congenital hypothyroidism, transmitted as a recessive trait, and caused by a homozygous mutation in the thyrotropin receptor (TS H-R). The initial diagnosis of thyroid agenesis, based on the absence of tr acer uptake on scintiscan, was incorrect, because ultrasound examination id entified severely hypoplastic thyroid tissue in the cervical region.