Van Wyk-Grumbach syndrome and trisomy 21.

The Van Wyk-Grumbach syndrome (VWGS) is characterized by severe hypothyroidism, peripheral precocious puberty, delayed bone age, hyperestrogenism, prepubertal luteinizing hormone, and elevated follicle-stimulating hormone. Patients with Down syndrome have a high susceptibility and prevalence of thyroid disorders. However, the coexistence of VWGS and trisomy 21 is uncommon. We present a case of a 5-year-old Mexican girl with Down syndrome, severe autoimmune hypothyroidism, pituitary enlargement, hyperprolactinemia, peripheral precocious puberty, multiple ovarian cysts, and delayed bone age, with a clinical diagnosis of VWGS. The patient presented with a remission of these manifestations after treatment with levothyroxine. Patients with Down syndrome, precocious puberty, hyperestrogenism, prepuberal luteinizing hormone, high follicle-stimulating hormone, and delayed bone age should be evaluated with a thyroid profile due to the possibility of VWGS.