In addition to these skeletal features, patients with GNAS mutations on the maternally inherited allele develop pseudohypoparathyroidism type 1A (PHP1A), in which patients exhibit obesity and resistance to multiple hormones requiring Gαs-coupled receptors [such as parathyroid hormone (PTH), thyrotropin (TSH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), calcitonin, glucagon, and growth hormone releasing hormone (GHRH)] [9, 13–18]. The gene discussed is PTH; the disease is pseudohypoparathyroidism type 1A.