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Reviewed May 2014

What is the official name of the CA12 gene?

The official name of this gene is “carbonic anhydrase XII.”

CA12 is the gene's official symbol. The CA12 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the CA12 gene?

The CA12 gene provides instructions for making a protein called carbonic anhydrase XII (CA XII), which belongs to a family of proteins known as carbonic anhydrases. These proteins carry out a chemical reaction that involves the molecules carbon dioxide and water and produces a negatively charged bicarbonate molecule (bicarbonate ion) and a positively charged hydrogen atom (known as a proton). Carbonic anhydrases can also carry out the reverse reaction, forming carbon dioxide and water from bicarbonate. Carbon dioxide, bicarbonate, and protons are involved in many functions in the body; by regulating the levels of these substances, carbonic anhydrases play roles in several important processes. The presence of protons and bicarbonate affect the relative acidity (pH) of cells; one function of some carbonic anhydrases is to help maintain the correct cellular pH.

CA XII is found in several tissues, including the sweat glands, kidneys, and large intestine. The protein likely helps regulate the transport of salt (sodium chloride or NaCl) in these tissues. Researchers suggest that channels that move salt in and out of cells are controlled in part by the pH of the cells. By regulating cellular pH, CA XII may be able to control salt transport. In sweat glands, CA XII is thought to play a role in determining how much salt is released from the body in sweat.

Does the CA12 gene share characteristics with other genes?

The CA12 gene belongs to a family of genes called CA (carbonic anhydrases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? in the Handbook.

How are changes in the CA12 gene related to health conditions?

isolated hyperchlorhidrosis - caused by mutations in the CA12 gene

At least one mutation in the CA12 gene causes isolated hyperchlorhidrosis, a condition characterized by abnormally high levels of salt in sweat that can lead to dehydration associated with low levels of sodium in the blood (hyponatremic dehydration). The gene mutation that causes this condition changes a single protein building block (amino acid) in the CA XII protein, replacing the amino acid glutamate at position 143 with the amino acid lysine (written as Glu143Lys or E143K). The function of the altered protein is reduced to about 70 percent of normal. In addition, the altered protein is more easily turned off (inhibited) than normal, which further reduces protein function. It is thought that the altered CA XII is less able to regulate pH, and it loses its ability to control how much salt is released in sweat, leading to hyperchlorhidrosis.

Researchers suggest that other tissues are seemingly unaffected by CA12 gene mutations because these tissues contain other carbonic anhydrases that compensate for the loss of CA XII function.

Where is the CA12 gene located?

Cytogenetic Location: 15q22

Molecular Location on chromosome 15: base pairs 63,323,531 to 63,382,110

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The CA12 gene is located on the long (q) arm of chromosome 15 at position 22.

The CA12 gene is located on the long (q) arm of chromosome 15 at position 22.

More precisely, the CA12 gene is located from base pair 63,323,531 to base pair 63,382,110 on chromosome 15.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about CA12?

You and your healthcare professional may find the following resources about CA12 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the CA12 gene or gene products?

  • carbonate dehydratase XII
  • carbonic anhydrase 12
  • carbonic dehydratase
  • CA-XII
  • tumor antigen HOM-RCC-3.1.3

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding CA12?

acidity ; amino acid ; atom ; bicarbonate ; Ca ; chloride ; dehydration ; gene ; intestine ; lysine ; molecule ; mutation ; NaCl ; pH ; protein ; proton ; sodium ; sodium chloride ; tumor

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (6 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.

Reviewed: May 2014
Published: February 8, 2016