Congenital hypothyroidism with hereditary, raised thyroxine binding globulin.

A boy with congenital hypothyroidism and hereditary raised thyroxine binding globulin is described. This hitherto unreported combination resulted in under treatment of the thyroid deficiency until serum thyroid stimulating hormone measurement became routinely available. Inadequate L-thyroxine replacement treatment between 2 and 7 years of age caused retarded bone maturation, poor growth velocity, and probably added to his educational difficulties.