Acatalasemia is a condition characterized by very low levels of an enzyme called catalase. Many people with acatalasemia never have any health problems related to the condition and are diagnosed because they have affected family members.Some of the first reported individuals with acatalasemia developed open sores (ulcers) inside the mouth that led to the death of soft tissue (gangrene). When mouth ulcers and gangrene occur with acatalasemia, the condition is known as Takahara disease. These complications are rarely seen in more recent cases of acatalasemia, probably because of improvements in oral hygiene.Studies suggest that people with acatalasemia have an increased risk of developing type 2 diabetes mellitus, which is the most common form of diabetes. A higher percentage of people with acatalasemia have type 2 diabetes mellitus than in the general population, and the disease tends to develop at an earlier age (in a person's thirties or forties, on average). Researchers speculate that acatalasemia could also be a risk factor for other common, complex diseases; however, only a small number of cases have been studied.