The other gene is PDE4D which is already reported to encode a cyclic AMP (cAMP) regulator which places PDE4D-related acrodysostosis in the same family of diseases as pseudohypoparathyroidism, pseudohypoparathyroidism, PRKAR1A-related acrodysostosis, and brachydactyly mental retardation syndrome, which are all characterized by cognitive impairment and short distal extremities (Lynch et al., 2013). This evidence concerns the gene PRKAR1A and Cognitive impairment.