Copy number variation of beta-defensins and relevance to disease

Beta-defensins are multifunctional proteins that have an important role in the innate immune system. A cluster of beta-defensin genes shows common and extensive variation in copy number in humans. This copy number has been associated with differing susceptibility to Crohn's disease and psoriasis. In this review, I summarise what is currently known about copy number variation (CNV) of beta-defensins, and discuss practical considerations when studying these genes, and copy number variation in general. I also suggest future directions for research, with an emphasis on improvement of methods for accurately typing CNV.