PPARG Pro12Ala — slightly reduced type 2 diabetes risk
One copy of the PPARG Pro12Ala variant detected.
You have one copy of a DNA change in PPARG that very slightly *lowers* type 2 diabetes risk.
Associated with a small *reduction* in lifetime type 2 diabetes risk (~20% per copy). The protective effect is modest but well replicated.
Your lifetime chance of type 2 diabetes is roughly 20% lower per copy than people without this version. The protective effect is small but consistent across many studies.
What this means
PPARG encodes a nuclear receptor central to fat-cell differentiation and insulin sensitivity — it's the molecular target of the thiazolidinedione diabetes drugs (pioglitazone). The Pro12Ala variant slightly reduces receptor activity, which paradoxically associates with slightly better insulin sensitivity and a modest reduction in diabetes risk. The effect is small but reproducible across many studies.
PPARG makes a protein that's central to how your fat cells develop and how well your body responds to insulin. It's also the target of a class of diabetes drugs called thiazolidinediones (such as pioglitazone). The Pro12Ala version slightly dials down the protein's activity, which — somewhat counterintuitively — is linked to slightly better insulin response and a modestly lower chance of developing type 2 diabetes. The effect is small but has been seen in many studies.
Caveats
- Effect size is small per allele.
- Lifestyle factors dominate the diabetes risk picture.
- The protective effect interacts with dietary fat intake in some studies.
References
- Altshuler et al. — The common PPARγ Pro12Ala polymorphism is associated with decreased risk of type 2 diabetes (Nature Genetics, 2000)
- Gouda et al. — The association between the peroxisome proliferator-activated receptor-γ2 (PPARG2) Pro12Ala gene variant and type 2 diabetes mellitus: a HuGE review and meta-analysis (American Journal of Epidemiology, 2010)