GNAS and acromegaly: Furthermore, activating mutations of GNAS affecting Gαs lead to McCune-Albright syndrome (post-zygotic mosaicism) and acromegaly (somatic mutations), while activating mutations of the thyrotropin-stimulating hormone (TSH) and luteinizing hormone (LH) receptor are associated with diseases such as hyperfunctioning thyroid adenoma and familial male precocious puberty, respectively54,55.