Elizabeth Landau, CNN, June 9, 2009
A single gene, called MYH9, may be responsible for many cases of kidney disease among African-Americans, researchers say.
Although doctors have blamed hypertension for causing common forms of kidney disease in African-Americans, new research shows that high blood pressure may not be the chief cause.
“The MYH9 gene association in African-American kidney disease is the most powerful genetic cause of a common disease yet discovered,” said Dr. Barry Freedman, professor of internal medicine and nephrology at Wake Forest University, who led a team of researchers in isolating the gene.
About 70 percent of African-Americans with non-diabetic forms kidney disease have the MYH9 gene, and many of them end up on dialysis, he said. The gene predisposes African-Americans to the kidney disease that was thought to stem from high blood pressure. It also gives them a higher risk of kidney disease associated with HIV.
Kidney disease is a serious health issue among African-Americans, who have a fourfold higher risk of developing all common forms of it than whites in the United States.
Still, the gene has not been shown to be the sole cause of kidney damage, Becker said. Diabetes and hypertension remain the most common causes of chronic kidney disease in the United States, he said.
Freedman conducted the research along with colleagues at the National Institute of Diabetes and Digestive and Kidney Diseases and the Family Investigation of Nephropathy and Diabetes Study.
The team discovered that the gene accounts for nearly half of kidney failure among African-Americans, including diabetic-related and non-diabetic-related kidney disease.
Researchers are now exploring what kinds of environmental triggers might cause the gene to promote kidney failure. HIV seems to trigger the gene and cause kidney failure, he said.
Many kidney doctors had theorized that African-Americans developed kidney disease more often than whites because they might not get to see their doctors as often, had more severe high blood pressure and faced other environmental stressors, Freedman said. But research shows that the risk variant of the MYH9 gene is more prevalent in among African-American populations than white populations and seems to explain much of the excess risk for non-diabetic kidney disease in African-Americans, he said.