Gene Tied to High Kidney Failure Rates in Blacks

Researchers said Thursday they have identified gene variants that help explain high rates of renal disease among African-Americans, who have a four times greater risk of kidney problems than whites.

According to the study published in the journal Science, variants in the APOL1 gene are the culprits, and likely evolved as a survival mechanism against lethal parasites in Africa.

Investigators at Beth Israel Deaconess Medical Center and the Universite Libre de Bruxelles found patients with focal segmental glomerulosclerosis (FSGS) and hypertension-attributed end-stage kidney disease (H-ESKD) had variants in the APOL1 gene that changed the APOL1 protein sequence.

"We found that the APOL1 risk genes for renal disease occur in more than 30 percent of African-American chromosomes," co-senior author Martin Pollak of Harvard Medical School said in a statement.

"In fact, the increased risk of kidney disease in individuals who inherited two copies of these variant forms of APOL1 is reported to be approximately 10-fold."

Quiz on Kidney
The kidneys are two bean-shaped organs, each about the size of a fist, and are located just below the rib cage, one on each side of your spine.

Healthy kidneys filter about half a cup of blood every minute, removing wastes and extra water to make urine. The urine flows from the kidneys to the bladder through two thin tubes of muscle called ureters, one on each side of your bladder. The bladder stores urine. The kidneys, ureters, and bladder are partof the urinary tract.

Pyeloplasty of Kidney
Animation showing Pyeloplasty surgical operation to relieve obstruction of the pelvi-ureteric junction of the kidney.

kidneys remove wastes and extra fluid from your body. Kidneys also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals-such as sodium, calcium, phosphorus and potassium-in your blood ().

Without this balance, nerves, muscles, and other tissues in the body may not work normally.

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Dialysis Efficiency Calculator or Kt/V calculator is an interactive tool that indicates how well dialysis is working for you and checks if enough water and waste products are cleared from your blood.

Kidneys also make hormones that help

Control your blood pressure
Make red blood cells
Keep your bones strong and healthy

FSGS is an injury to the kidney's filtering system and ESKD indicates a kidney failure so severe the patient needs dialysis or a kidney transplant.

Kidney problems, which see about half a million US patients require dialysis treatment to replace their failed organs, are particularly pronounced among African-Americans.

Using information from the 1000 Genomes Project DNA data bank, the researchers singled out candidate genetic variants and tested DNA sample sets for their presence.

They found that the APOL1 variants G1 and G2 were linked to a greater risk of both FSGS and hypertension-attributed ESKD in African-Americans.

"G1 and G2 both changed the coding sequence of APOL1," explained Pollak. "Further analyses revealed that these very same genetic variants conferred human immunity against the parasite responsible for sleeping sickness."

The tsetse fly transmits the African trypanosome parasite, which causes sleeping sickness. The disease, not found outside Africa, causes severed nervous system disorders and can ultimately lead to brain damage, coma or death.

Source-AFP