Metrorrhagia and precocious puberty revealing primary hypothyroidism in a child with Down's syndrome.

We report a child with Down's syndrome in whom metrorrhagia and precocious puberty revealed primary autoimmune hypothyroidism. The patient had a decreased growth velocity, exaggerated weight gain, bone age delay, and bilaterally enlarged multicystic ovaries. Delays in the diagnosis and treatment of hypothyroidism can lead to this peculiar presentation.