AXIN2 mutations result in hypodontia and oligodontia associated with colorectal cancer.39It was found that the oligodontia caused by the AXIN2 gene was more severe than that described for mutations in MSX1 and PAX9 genes; there were more missing molars, premolars, upper lateral incisors, and lower incisors.40 The gene discussed is MSX1; the disease is tooth agenesis.