complement factor H related 5
The CFHR5 gene provides instructions for making a protein called complement factor H-related 5. The precise function of this protein is unknown. However, its structure is similar to that of a protein called complement factor H (which is produced from the CFH gene). This similarity provides clues to the probable function of complement factor H-related 5.
Complement factor H regulates a part of the body's immune response known as the complement system. The complement system is a group of proteins that work together to destroy foreign invaders (such as bacteria and viruses), trigger inflammation, and remove debris from cells and tissues. This system must be carefully regulated so it targets only unwanted materials and does not damage the body's healthy cells. Complement factor H helps to protect healthy cells by preventing the complement system from being turned on (activated) when it is not needed. Studies suggest that complement factor H-related 5 also plays a role in controlling the complement system.
Several mutations in the CFHR5 gene have been found to cause a rare form of kidney disease called C3 glomerulopathy. This disorder damages the kidneys and can lead to end-stage renal disease (ESRD), a life-threatening condition that prevents the kidneys from filtering fluids and waste products from the body effectively.
The most common CFHR5 gene mutation has been identified in people from the Mediterranean island of Cyprus. This genetic change abnormally copies (duplicates) regions of the CFHR5 gene known as exons 2 and 3. The duplication alters the structure and function of complement factor H-related 5, preventing it from regulating the complement system effectively. As a result, the complement system becomes overactive, which damages structures called glomeruli in the kidneys. These structures are clusters of tiny blood vessels that help filter waste products from the blood. Damage to glomeruli prevents the kidneys from filtering waste products normally and can lead to ESRD.
Several other changes involving the CFHR5 gene do not cause C3 glomerulopathy directly but appear to increase the likelihood of developing the disorder. It is unclear how variations in this gene affect the regulation of the complement system, and researchers are still working to determine how these genetic changes contribute to disease risk.
Genetics Home Reference provides information about atypical hemolytic-uremic syndrome.
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- complement factor H-related 5
- complement factor H-related protein 5
- factor H-related protein 5