Central Precocious Puberty in a Girl with McCune-Albright Syndrome Responds to Treatment with GnRH Analogue

Abstract

GnRH analogues have been used with variable success for the treatment of precocious puberty in children with McCune-Albright syndrome (MAS). In general, children with a bone age of less than 13.5 yr have been reported not to have benefitted from GnRH therapy. In contrast, we have successfully treated a young girl with MAS and--probably secondary--central precocious puberty using Decapeptyl, a long acting GnRH analogue. The girl with MAS presented at the age of six years with café au lait spots, osseous lesions and precocious puberty. At initial presentation height was 130.7 cm (> 97 percentile), weight 27.5 kg (> 97 percentile), Tanner stage B3, PH3. Bone age was 11 yr. Magnetic resonance imaging of the brain was normal. Endocrine function tests were normal with the exception of biochemical evidence of central precocious puberty: LHRH test: LH 0.9/20.3, FSH 4.3/12.7 (mU/ml), E2 15.6 pg/ml. Therapy was started with 3.75 mg GnRH analogue i.m. every four weeks and was intensified two years after the beginning of therapy to 3.75 mg i.m. every three weeks. Three years after the start of treatment bone age was 12 yr and growth velocity was 2.5 cm/year. Tanner stage was B3, PH3 and LHRH testing revealed biochemical evidence for suppression of gonadotropins: LH < 0.5/1.0, FSH 1.9/2.5 (mU/ml). We hypothesize that a subgroup of patients with MAS might present with a central form of precocious puberty. This may be particularly so in children with a bone age greater than or equal to 11 yr. Central precocious puberty in these children might follow extensive sex steroid exposure due to the peripheral precocious puberty induced by the activating mutation of the Gs protein gene. This central form of precocious puberty responds to therapy with GnRH analogues.