Unusual phenotypical variations in a boy with McCune-Albright syndrome.

BACKGROUND

McCune-Albright syndrome (MAS) typically comprises the constellation of polyostotic fibrous dysplasia, café-au-lait spots, and associated endocrinopathies including gonadotropin-independent precocious puberty, excessive growth hormone production and gigantism, hyperthyroidism, and hyperparathyroidism.

OBJECTIVE

We report the unique case of a boy with the diagnostic criteria of MAS accompanied by atypical short stature and macroorchidism without precocious puberty.

PATIENT: An 8.4-year-old prepubertal boy presented with a history of recurrent bone fractures, multiple café-au-lait spots, bilateral macroorchidism, and short stature. X-ray of the extremities was consistent with polyostotic fibrous dysplasia. Serum inhibin B (IB) and anti-müllerian hormone (AMH) were elevated; testosterone, LH, and FSH were normal for age.

RESULTS

PCR-based DNA analysis of bone tissue revealed a substitution of arginine for cysteine at position 201 in the G(s)alpha protein resulting in activation of the G(s)alpha subunit.

CONCLUSIONS

We report a second case of MAS associated with macroorchidism. In this case, isolated Sertoli cell hyperfunction was also associated with microlithiasis and was not associated with peripheral precocious puberty. Short stature not associated with GH-IGF-1 axis abnormality was a second anomalous finding in this case. Our experience suggests that the phenotypic variation in MAS is wider than previously described.