Considering human disease relevant to CNP KO rats, we must compare the phenotypes of CNP KO rats with those of acromesomelic dysplasia, type Maroteaux (AMDM), which is caused by biallelic mutations in the gene encoding NPR-B, the bioactive receptor for CNP [12]. This evidence concerns the gene NPR2 and acromesomelic dysplasia 1, Maroteaux type.