GNAS and pseudohypoparathyroidism type 1A: Patients with maternally derived germline GNAS mutations have been shown to develop pseudohypoparathyroidism 1A (PHP1A) with associated obesity and hormonal resistance, while those with paternally derived germline GNAS mutations have been shown to develop pseudopseudohypoparathyroidism (PPHP) without associated obesity or hormonal resistance [19].