Race and IgA nephropathy

Researchers have found five regions in the human genome that increase susceptibility to immunoglobulin A (IgA) nephropathy, a major cause of kidney failure worldwide. 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. Worldwide prevalence of IgA nephropathy appears highest in Asia and southern Europe, and is responsible for most cases of kidney failure in those populations. The prevalence in the United States is much lower - up to 10%, although Native Americans from New Mexico have reported rates as high as 38%. IgA nephropathy is most common in Asia, intermediate in prevalence in Europeans and rare in Africans. The researchers found that the frequency of genetic risk variants was similarly highest in Chinese people, intermediate in Europeans and lowest in Africans. This suggests that their higher frequency in Asians may in part account for increased prevalence in this population.