A new study has linked a gene, which forms part of our body's first line of defence against infection, to an increased risk of a type of kidney disease.

The University of Nottingham study found that the difference in the number of copies of the alpha-defensin genes was a major genetic factor in developing the condition IgA nephropathy, also known as Berger's Disease.

Researcher John Armour said that the observation that variation in the gene numbers for these alpha-defensin genes is strongly correlated with risk of IgA nephropathy creates an interesting puzzle.

He added that the data overwhelmingly support the association, but researchers still don't understand what the connection might be between alpha-defensins and molecular events that cause the kidney problems.

The team looked at genetic variation in more than 1,000 patients with IgA nephropathy, compared with more than 1,000 people without the condition, and found a significant difference in the numbers of alpha-defensin genes between the two groups.

Alpha-defensins are proteins that kill bacteria as part of the innate immune system, our first line of defence against infection.

Although the findings do not immediately suggest new therapies for the disorder, they will improve our chances of identifying those who are most at risk and offer a new line of investigation to understand exactly how the defensin gene copy number variants lead to kidney disease. The team is already undertaking the next stage of research to further develop our knowledge.

The study is published in the journal Science Translational Medicine.