Scientists have discovered five regions in the human genome that increase susceptibility to immunoglobulin A (IgA) nephropathy, a major cause of kidney failure worldwide - systematically identifying those that point to a tendency for IgA nephropathy, or a protection against it.
"The study is unique in identifying the biological pathways that mediate IgA nephropathy, mapping the way for further study that may reveal practical targets for diagnosis and treatment," said Ali Gharavi, Division of Nephrology at Columbia University in New York City, the principal investigator.
"The cause and development of IgA nephropathy is poorly understood. Many biological pathways have been suggested, but none has been conclusive until now," he said.
Researchers looked at the genes of 3,144 people of Chinese and European ancestry, all of whom have IgA nephropathy.
The disease occurs when abnormal IgA antibodies deposit on the delicate filtering portion of the kidney and form tangles. The immune system tries to get rid of the tangles, but the kidneys are caught in the crossfire, further destroying the delicate filters.
Some of the genes implicated in the study are especially interesting because they play a role in other (not kidney-related) immune disorders. For example, the complement factor H region, called a locus, has been associated with macular degeneration, a progressive eye disease that can result in blindness; and susceptibility to meningococcal infection, the bacteria that causes meningitis.
The study has been published in the Nature Genetics.