In humans, not only homozygous loss-of-function mutations in the NPR-B gene, which are the causes of acromesomelic dysplasia type Maroteaux, a form of skeletal dysplasia with severely impaired endochondral bone growth [12, 13], but also heterozygous mutations in that gene [14–18], reportedly caused impaired skeletal growth. This evidence concerns the gene NPR2 and Acromesomelic dysplasia, Maroteaux type.