PRKAR1A and brachydactyly: PTH resistance and brachydactyly (but in a more severe form) are also present in acrodysostosis with multihormonal resistance ACRDYS1 (or iPPSD4, OMIM#101800) [11–13], which is associated with mutations in the gene coding for the cAMP-dependent protein kinase type 1 regulatory subunit protein (PRKAR1A) [14].