Acatalasemia (acatalasemia) - CAT gene.

The acatalasemia is a disorder characterized by very low concentrations of the enzyme catalase. Many people with acatalasemia never have health problems related to this deficiency and are diagnosed because other family members are affected. Some individuals with acatalasemia develop ulcers inside the mouth that generate gangrene. When mouth ulcers and gangrene associated with acatalasemia, this disease is known as Takahara disease. These complications are rarely seen in the most recent cases of acatalasemia, probably due to improvements in oral hygiene.

Studies suggest that people with acatalasemia have a higher risk of developing diabetes mellitus type 2. In addition, it is believed that acatalasemia could also be a risk factor for other common and complex diseases however, only a small number of cases have They have been studied.

This process is due to mutations in the CAT gene, located on the short arm of chromosome 11 (11p13). This gene encodes the enzyme catalase subunits. Four identical subunits, each attached to a molecule of heme iron, form functional enzyme. Catalase is active in cells and tissues throughout the body, where hydrogen peroxide (H2O2) is decomposed into oxygen molecules (O2) and water (H2O). Hydrogen peroxide is produced by chemical reactions within the cells. At low concentrations, it is involved in several pathways chemical signaling, but in high concentrations is toxic to cells. If hydrogen peroxide is not decomposed by catalase, additional reactions make it reactive oxygen species that can damage DNA, proteins and cell membranes.

They have identified at least 13 mutations in the gene responsible for acatalasemia CAT. These genetic changes reduce the activity of catalase to less than 10% of normal. The deficiency of this enzyme may allow the hydrogen peroxide to accumulate to toxic levels in certain cells. For example, the hydrogen peroxide produced by the bacteria can accumulate in the mouth and soft tissue damage, leading to mouth ulcers and gangrene. An accumulation of hydrogen peroxide can also damage the pancreatic beta cells, which release insulin to control blood glucose. It is believed that the malfunction of the beta cells underlying the increased risk of type 2 diabetes in people with acatalasemia. It is unclear why some people have no health problems associated with the lack of activity of catalase.

The acatalasemia has an autosomal recessive inheritance pattern, which means that both copies of the CAT gene in each cell have mutations. When both copies of the gene are altered, the catalase activity is reduced to less than 10% of normal. When only one of the two copies of the CAT gene has a mutation, the activity of the catalase is reduced by about half. This reduction in activity of catalase is often called hypocatalasemia. Like acatalasemia, the hypocatalasemia usually does not lead to any health problems.

Tests in IVAMI: in IVAMI perform detection of mutations associated with acatalasemia, by complete PCR amplification of the exons of the CAT gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).