A pseudohypoparathyroidism characterized by isolated renal parathyroid hormone (PTH) resistance resulting in hypocalcemia, hyperphosphatemia and elevated PTH levels that has_material_basis_in mutations that alter the methylation pattern of GNAS on 20q13.32. Mutations in GNAS, GNAS-AS1, and STX16 have been shown to alter the methylation pattern of GNAS.