PTHLH and pseudohypoparathyroidism: To aid in clinical classification, the European Network for the Study of Pseudohypoparathyroidism (EuroPHP Network) introduced the inactivating PTH/PTHrP signaling disorder (iPPSD) system, a molecularly based taxonomy using numbered subtypes to delineate genotypic and phenotypic features (Pereda et al., 2021).