Diminished prolactin reserve with myotonic dystrophy.

Isolated deficiency of prolactin secretion is an uncommon condition of unknown clinical significance. A unique case of prolactin deficiency in association with myotonic dystrophy is described. It is unlikely that absence of prolactin is responsible for the clinical features associated with myotonic dystrophy, since two other patients with myotonic dystrophy did not have prolactin deficiency.