( CNN ) -- A single gene , called MYH9 , may be responsible for many cases of kidney disease among African-Americans , researchers say . Dr. Barry Freedman , right , speaks with a colleague in a dialysis center at Wake Forest Baptist Medical Center . 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 . `` This genetic finding will forever change the way that we categorize the causes of kidney disease . It has the potential to lead to new treatment options to prevent this devastating disease , '' Freedman said . 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 . Dr. Bryan Becker , president of the National Kidney Foundation , called the research `` seminal work '' in identifying a gene associated with common kidney diseases . 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 . There is no reason to screen all African-Americans for the risk variant of this gene , or even all African-Americans with high blood pressure , because it is common among all African-Americans , Freedman said . Genetic screening would be most useful for people who have close relatives on dialysis , meaning they are at high risk , or individuals who want to donate kidneys , he said . There have not been studies on who should be screened , 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 . It is still important for people to treat hypertension , which can speed up the weakening of kidneys in people with kidney disease , Freedman said . Untreated high blood pressure also leads to heart attack and stroke , he said . Dr. Michael Roizen , chief wellness officer at the Cleveland Clinic and author of `` RealAge : Are You as Young as You Can Be ? '' said the question still remains whether the gene initiates hypertension and kidney disease , and to what extent hypertension causes kidney disease . `` Most physicians would say that the reason blood pressure is so important is that higher levels of blood pressure cause kidney disease , and kidney disease cause higher levels blood pressure , and there 's a vicious circle , '' he said . Becker also noted that researchers will have to sort out the interactions between the MYH9 gene and hypertension , as well as the gene and diabetes . No one knows why African-Americans tend to have a higher risk for hypertension . One controversial hypothesis , known as the Middle Passage theory , is that black people who survived the harrowing trip across the Atlantic Ocean from Africa in the holds of ships did so because their bodies were better able to preserve salt , allowing them to avoid death by dehydration . Therefore , the theory goes , some African-Americans have a higher prevalence of `` salt-sensitive hypertension '' : Their blood pressure increases by unusually high amounts in response to salt . This theory has not been proved , or even widely studied , but the idea continues to permeate popular culture and generate discussion . The isolation of the MYH9 gene does not necessarily refute the theory , Roizen said . `` To survive , they had to retain salt , and they had to have a gene to help them do that , '' he said .
Study : Gene ##tics African - Americans to common heart disease . Interactions between the same gene and disease are still unknown . It is still important for people to treat hypertension , they say .