It has been established in both humans and mouse models [1] that the metabolic and hormonal distinctions between PHP1A and PPHP are secondary to partial paternal imprinting of GNAS in specific tissues, many of which are endocrine, such as the renal proximal convoluted tubules, thyroid, gonads, and pituitary [13–15, 21–24]. Here, GNAS is linked to pseudopseudohypoparathyroidism.