Diabetes mellitus
Experiments in animal models have shown that a reduction in Pdx1 expression can cause symptoms that are characteristic of Diabetes mellitus type 1 and Diabetes mellitus type 2. Furthermore, expression of Pdx1 is lost in gastric cancers, suggesting a role for the gene as a tumor suppressor. Maturity onset diabetes of the young (Type 4) can be caused by heterozygous mutations in Pdx1. The fat sand rat "Psammomys obesus", a species with susceptibility to Diabetes mellitus type 2 symptoms, has a highly divergent "Pdx1" gene sequence compared with other mammals.