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Reviewed September 2014
What is acatalasemia?
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.
How common is acatalasemia?
More than 100 cases of acatalasemia have been reported in the medical literature. Researchers estimate that the condition occurs in about 1 in 12,500 people in Japan, 1 in 20,000 people in Hungary, and 1 in 25,000 people in Switzerland. The prevalence of acatalasemia in other populations is unknown.
What genes are 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.
Read more about the CAT gene.
How do people inherit acatalasemia?
Acatalasemia has an autosomal recessive pattern of inheritance, which means both copies of the CATgene in each cell have mutations. When both copies of the gene are altered, the activity of catalase is reduced to less than 10 percent of normal.
When only one of the two copies of the CAT gene has a mutation, the activity of catalase is reduced by approximately half. This reduction in catalase activity is often called hypocatalasemia. Like acatalasemia, hypocatalasemia usually does not cause any health problems.
Where can I find information about diagnosis or management of acatalasemia?
These resources address the diagnosis or management of acatalasemia and may include treatment providers.
You might also find information on the diagnosis or management of acatalasemia in Educational resources and Patient support.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about acatalasemia?
You may find the following resources about acatalasemia helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for acatalasemia?
- catalase deficiency
What if I still have specific questions about acatalasemia?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
- What does it mean if a disorder seems to run in my family?
- What are the different ways in which a genetic condition can be inherited?
- If a genetic disorder runs in my family, what are the chances that my children will have the condition?
- Why are some genetic conditions more common in particular ethnic groups?
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding acatalasemia?
autosomal ; autosomal recessive ; bacteria ; cell ; deficiency ; diabetes ; diabetes mellitus ; DNA ;enzyme ; gene ; gingival ; hormone ; hydrogen peroxide ; inheritance ; insulin ; mutation ; necrosis ;oxygen ; pancreas ; pattern of inheritance ; population ; prevalence ; reactive oxygen species ;recessive ; soft tissue ; tissue ; toxic
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (5 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.