Given the epigenetic etiology of PHP1B, we advocate concurrent WES and targeted GNAS methylation analysis in patients meeting any of the following criteria: biochemical triad of hypokalemia with concomitant hypocalcemia and elevated PTH; intracranial calcifications on neuroimaging; and suboptimal or transient responses to targeted electrolyte supplementation. Here, GNAS is linked to pseudohypoparathyroidism type 1B.