APOL1 G2 — kidney disease risk variant
An APOL1 G2 allele has been detected.
You have at least one copy of the APOL1 G2 kidney risk version.
The G2 allele is one of two APOL1 risk variants whose effect emerges in pairs. Inheriting two risk alleles (G1/G1, G1/G2, or G2/G2) substantially increases lifetime risk of several forms of kidney disease. One copy alone does not meaningfully raise risk.
G2 is one of two APOL1 risk versions whose effect only really shows up when you have two copies in any combination (G1/G1, G1/G2, or G2/G2). With two risk copies, your lifetime risk of certain kidney diseases is substantially higher. One copy alone doesn't meaningfully raise risk.
What this means
G2 is a small deletion in APOL1 that, like the G1 missense variant, provides resistance to trypanosome parasites at the cost of increased kidney disease risk when present in two copies. The combined "G1+G2 risk genotype" (any pair) is what clinicians stratify on. Whether to test before kidney donation has become an active area of nephrology practice.
G2 is a small piece of DNA missing from the APOL1 gene. Like the related G1 change, it evolved to protect against the trypanosome parasite that causes sleeping sickness, which is why it's most common in people with recent sub-Saharan African ancestry. The trade-off is that having two risk copies — any combination of G1 and G2 — substantially raises the lifetime risk of several kidney diseases. Doctors look at the combined picture: any pair counts. Whether to do APOL1 testing before donating a kidney is now an active conversation in kidney care.
Caveats
- Effect is recessive — one allele is not a clinical concern.
- Most two-allele carriers do not develop kidney disease over their lifetime.
- Blood pressure and glucose control remain the dominant modifiable factors.
Populations
- Found almost exclusively in people of recent sub-Saharan African ancestry