Heterozygous inactivating mutations in Gsα-coding GNAS exons can cause different phenotypic expressions that vary from pseudohypoparathyroidism (PHP) to pseudo-pseudohypoparathyroidism (PPHP) to Progressive Osseous Heteroplasia (POH) [3, 10]. The gene discussed is GNAS; the disease is pseudohypoparathyroidism type 1A.