In the case of acrodysostosis with multihormonal resistance (ACRDYS1, OMIM#101800), the gene responsible is cAMP-dependent protein kinase A (PRKAR1A), which has been localized to 17q24.2 and is involved in the signalling pathway downstream of GNAS. This is the reason for resistance to PTH and other hormones, as in PHP [44,48]. The gene discussed is PTH; the disease is acrodysostosis.