Severe congenital hypopituitarism with low prolactin levels and age-dependent anterior pituitary hypoplasia: a clue to a PIT-1 mutation.

A 20-month-old boy presented with severe congenital growth hormone, thyrotropin, and prolactin deficiencies resulting from a de novo mutation of the PIT-1 gene. This form of congenital hypopituitarism should be suspected if pituitary anatomy is normal, especially if prolactin levels are low and, in boys, if the external genitalia are normal. Pituitary atrophy appears to be an age-dependent phenomenon in this condition.