Bone Abstracts

Introduction: Albright-McCune Sternberg syndrome (SAMS) is a rare disorder which originates in a germinal mutation of gene GNAS1, which codifies the alpha subunit of protein G (Gsa). It is characterized by a typical phenotype which includes polyostotic fibrodysplasia, precocious puberty independent from gonadotropins, cafe-au-lait spots and a series of endocrine abnormalities. The most common mutations include a cysteine or histidine for arginine substitution in codon 201 of exon 8 (R201C or R201H) or a glutamine for arginine or leucine substirution in codon 227 of exon 9 (Q227L or Q227L). Woman to male relation is 10–1.

Material and methods: To describe three patients with MaCCune-Albright syndrome and a GNS1 mutation.

Results: 5 year-old boy with café-au-lait spots in the face and thorax, easy fatigability, generalized osteomuscular pain, frequent sinusitis, without pubic hair and testes of 5 ml. Bone scan shows activity on both femoral bones. Low serum testosterone and no FSH or LH response to GnRH. Study by allelic specific PCR and enzymatic digestion reveal an arginine 201 to histidine mutation. The second patient is a Girl with café-au.lait spots and seriously bone fybrodi¡syplasia with compromise of her hip and cranium, She developed hyperthyroidism and seriously compromise of optic formane due to dysplasia, with severe and progressive vaginal bleeding, due to high growth velocity, analisys form gene was maden and excess of growth hormone waqs confirmed, Alendronate and Octreotide was begun with stablisatrion of cranial compromise and normalization of GH, IGF1 and growth velocity.

The third patient is a 5-years-old boy, with serioiusly compromise of left proximal femur, alendronate was started with development of adynamic bone and high values of bone densitometry, the molecular study was negative.

Analysis and conclusions: We describe three patients with the McCune-Albright syndrome and a GNAS1 mutation Two of which have with a gonadotropin independent precocious puberty. Follow up will be important to rule out other endocrinopathies, specially growth hormone excess. Results of treatment with aromatase inhibitors, GnRH analogues or biphosphonates have not been helpful in all cases, and the diversity of evolution is presented.

Disclosure: The authors declared no competing interests.