Precocious Puberty during Treatment for Prolonged Hypothyroidism in a Boy with Down Syndrome: A Case Report

Abstract

We saw a case of precocious puberty in a body with Down syndrome, during treatment for autoirnmune hypothyroidism caused by interferon therapy for chronic Epstein-Barr virus infection. One year after the start of l-thyroxine supplementation, his somatic growth spurt and penile development started. His growth rate was fairly high for a patient with Down syndrome who generally have a slow pubertal growth spurt. Serum gonadotropins and testosterone were at the pubertal levels of boys of normal karyotype. We thought it better not to suppress his puberty, because it seemed that his growth rate may be reduced too much by lowered testosterone and the pubertal spurt may not recover fully after cessation of the gonadal suppression therapy. He has already gained 25cm since the start of the growth spurt and still continues to grow at the rate of 9 cm a year without any treatment.