What are the genetic changes related to acatalasemia ?
Mutations in the CAT gene can cause acatalasemia. This gene provides instructions for making the enzyme catalase, which breaks down hydrogen peroxide molecules into oxygen and water. Hydrogen peroxide is produced through chemical reactions within cells. At low levels, it is involved in several chemical signaling pathways, but at high levels it is toxic to cells. If hydrogen peroxide is not broken down by catalase, additional reactions convert it into compounds called reactive oxygen species that can damage DNA, proteins, and cell membranes.  Mutations in the CAT gene greatly reduce the activity of catalase. A shortage of this enzyme can allow hydrogen peroxide to build up to toxic levels in certain cells. For example, hydrogen peroxide produced by bacteria in the mouth may accumulate in and damage soft tissues, leading to mouth ulcers and gangrene. A buildup of hydrogen peroxide may also damage beta cells of the pancreas, which release a hormone called insulin that helps control blood sugar. Malfunctioning beta cells are thought to underlie the increased risk of type 2 diabetes mellitus in people with acatalasemia. It is unclear why some people have no health problems associated with a loss of catalase activity.  Many people with reduced catalase activity do not have an identified mutation in the CAT gene; in these cases, the cause of the condition is unknown. Researchers believe that other genetic and environmental factors can also influence the activity of catalase.