Gene copies and kidney disease 20/2/06. By Rachael Brooker Variation in the number of copies of the gene Fcgr3 an individual carries alters their susceptibility to the kidney disease glomerulonephritis.

While small variations in the sequence of a gene have long been associated with differences in gene function, it is only recently that the significance of gene copy-number variation has begun to be appreciated. A difference in the number of copies of a gene an individual carries has recently been associated with predisposition to disease.

Timothy Aitman (Medical Research Council Clinical Sciences Centre and Imperial College London) and colleagues examined strains of rats that vary in their susceptibility to glomerulonephritis. They found that susceptible strains carry one copy of the Fcgr3 gene, which produces a protein involved in the inflammatory response, whereas resistant strains carry an additional copy. They then examined copy number of the corresponding gene, FCGR3B, in humans with glomerulonephritis, and found that copy number varied between zero and four, and that individuals with glomerulonephritis had fewer copies of Fcgr3.

The authors suggest that copy-number variation may be a more significant factor in disease susceptibility than was previously thought.

Image credit: Wellcome Library, London

Further reading

Aitman TJ, et al. Copy number polymorphism in Fcgr3 predisposes to glomerulonephritis in rats and humans. Nature. 2006 Feb 16;439(7078):851-5. Abstract