What causes McCune Albright syndrome ?
What causes McCune Albright syndrome? McCune Albright syndrome (MAS) is caused by a change (mutation) in the GNAS gene. This gene provides instructions for making part of a protein that ultimately influences many cell functions by regulating hormone activity. GNAS gene mutations that cause MAS result in a protein that causes the enzyme adenylate cyclase to be constantly turned on. This, in turn, leads to over-production of several hormones, resulting in the signs and symptoms of MAS.