NPR-2 the natriuretic peptide receptor B guanyl cyclase GC-B gene has been identified as responsible for causing AMDM; it is a receptor for C-type natriuretic peptide (CNP) that acts locally as a paracrine and /or autocrine regulator in many tissues including bone [33]. The gene discussed is CNP; the disease is acromesomelic dysplasia 1, Maroteaux type.