Senin, 09 Mei 2011

Albright syndrome

Albright syndrome: A genetic disorder of bones, skin pigmentation and hormonal problems with premature sexual development. Also called McCune-Albright syndrome and polyostotic fibrous dysplasia. Albright syndrome (McCune¾Albright syndrome) Consists of polyostotic fibrous dysplasia (multiple bones affected), patchy skin pigmentation (referred to as cafe-au-lait spots), and an endocrine abnormality (usually precocious puberty in girls). Facial asymmetry affects up to 25% of cases.

What gene mutation cause mc Cune Albright’s syndrome?

McCune-Albright syndrome is caused by a mutation in the GNAS gene. The GNAS gene provides instructions for making one part of a protein complex called a guanine nucleotide-binding protein, or a G protein.

In a process called signal transduction, G proteins trigger a complex network of signaling pathways that ultimately influence many cell functions by regulating the activity of hormones. The protein produced from the GNAS gene helps stimulate the activity of an enzyme called adenylate cyclase. GNAS gene mutations that cause McCune-Albright syndrome result in a G protein that causes the adenylate cyclase enzyme to be constantly turned on (constitutively activated). Constitutive activation of the adenylate cyclase enzyme leads to over-production of several hormones, resulting in the signs and symptoms of McCune-Albright syndrome.

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