PTH and pseudohypoparathyroidism type 1A: In 2016, Thiele et al. 27 classified acrodysostosis as an inactivating parathyroid hormone/parathyroid hormone-related peptide signalling disorder (iPPSD), based on shared characteristics with other diseases that affect the PTH/PTHrP and cAMP/PKA signalling pathways e.g. pseudohypoparathyroidism (PHP).