A study by researchers at the National Institutes of Health (NIH) and their collaborators revealed a significant genetic risk factor for kidney disease in people in Ghana and Nigeria. Their study showed that having a single risk variant in a gene known as APOL1 can significantly increase the risk of developing kidney disease. APOL1 is important for the immune system and gene variants are linked to an increased risk of chronic kidney disease. The study is published in the New England Journal of Medicine and was conducted by researchers from the Human Heredity and Health in Africa Kidney Disease Research Network (H3Africa).
Previous research established that genomic variants in APOL1 increase the risk of developing chronic kidney disease among African Americans. However, not much is known about how these genomic variants affect people in West African countries, where many African Americans have genetic ancestry. Studying how these genomic variants contribute to chronic kidney disease in West Africans and people of West African ancestry may also help inform the risk of kidney disease in many Americans.
“Our study provides data on West Africans that will help us better understand the risk of chronic kidney disease associated with APOL1 variants,” said Adebowale A. Adeyemo, MBBS, co-author of the study and deputy director and chief. Scientific officer at the Center for Genomics and Global Health Research at the National Human Genome Research Institute (NHGRI) at the NIH. “By comparing this study to previous studies involving the African American population, we can gain a deeper understanding of the effects of these high-risk APOL1 variants. Knowing your genetic risk for a disease, such as kidney disease, can help you make more informed decisions about their health and potentially lead to earlier interventions.
More than 8,000 people from Ghana and Nigeria participated in the study, including almost 5,000 people with chronic kidney disease at various stages and more than 800 people who had kidney biopsies that confirmed their disease.
The study found that almost a third of people in these two countries carry APOL1 variants that increase the risk of chronic kidney disease. While these APOL1 variants are most commonly seen in people of West African descent, other studies have found these variants in people from Europe, Asia, and Central and South America.
The researchers also found that having a risk variant in one copy of the APOL1 gene increases the risk of developing chronic kidney disease, contrary to previous studies in the African-American population that suggested that both copies of APOL1 must contain such variants to increase the overall risk. . One risk variant increases the risk of chronic kidney disease by 18%, while two risk variants, one in each copy of APOL1, increase the risk by 25%.
These APOL1 risk variants also dramatically increase the chance of developing a rare kidney disease called focal segmental glomerulosclerosis, which is scarring of kidney tissues.
“The findings of a particular study or a specific ancestral group are often considered valid for all of humanity, but there is often substantial diversity even within specific ancestries or ethnic groups,” says Dr. Adeyemo. “This study highlights the importance of studying diverse populations around the world when studying the genomics of human diseases so that genomic medicine can equitably benefit people around the world.”
More than 1 in 7 American adults has chronic kidney disease; An estimated 37 million Americans, and African American, Hispanic and Native American populations, are more likely to develop the disease. Both genetic and environmental factors, including social factors such as smoking, lack of exercise, an unhealthy diet, and lack of access to health care, contribute to the risk of kidney disease. People with kidney disease may not have noticeable symptoms in the early stages of the disease. Additionally, people with diabetes or hypertension have a higher risk of developing kidney disease. As the kidneys slowly become damaged over time, they cannot filter the blood properly, causing a buildup of waste in the body.
As the disease progresses, additional functions of the kidneys are affected, such as stimulating red blood cell production and maintaining the body’s calcium balance. The disease can lead to other health problems, such as strokes and heart attacks.
“More research with participants in the United States can help us understand how APOL1 variants affect the kidney,” says Paul Kimmel, MD, program director at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and co-author of the study. . “Overall, we hope that these findings can provide information to improve the health of patients at risk for and with kidney disease.”