Of these models, the oc/oc, Clcn7−/−, and gl/gl mice carry mutations in the genes with the highest incidence in human IMO (Tcirg1, Clcn7, and Ostm1, respectively) and thus most substantially facilitated study of the pathophysiology of the most severe forms of human osteopetrosis.15 This evidence concerns the gene TCIRG1 and osteopetrosis.