OMIM ID:
McCune-Albright Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
This disorder is of interest to ophthalmologists because compression of the optic nerve can occur from fibrous dysplasia of the canal. However, this occurs only in some cases. The risk of optic neuropathy is higher in patients with elevated levels of growth hormone.
Systemic Features
This disorder is clinically heterogeneous because of the variable degree of involvement of all bony tissue. The primary manifestations are secondary to endocrine dysfunction and fibrous dysplasia. Thyrotoxicosis, Cushing syndrome, pituitary gigantism, hearing deficits, and precocious puberty (in both sexes) are common. The skin often has a cafe-au-lait pattern of pigmentation.
Genetics
Inheritance
Postzygotic activating mutations in the GNAS gene on chromosome 20 (20q13.2) are likely responsible for this disorder although too few familial cases have been reported to document a mode of inheritance. It has been suggested that an autosomal dominant lethal gene is involved with survival only in the presence of significant mosaicism.