HLA-B
Major Histocompatibility Complex, Class I, B
What it does
Carrier status is associated with severe drug-hypersensitivity reactions to abacavir, allopurinol, and carbamazepine.
Why this matters for Black patients
HLA-B*5701 (abacavir) is rare in African ancestry but high in European ancestry — a screening shift. HLA-B*5801 (allopurinol) is more common in African ancestry than in many other groups, with severe Stevens-Johnson syndrome risk.
Common variants
| Variant | Phenotype | African | European |
|---|---|---|---|
| *5701 | Severe abacavir hypersensitivity | 0.005 | 0.060 |
| *5801 | Severe allopurinol hypersensitivity | 0.040 | 0.005 |
Note: This page is reference information, not medical advice. Pharmacogenomic differences are about ancestry, not race; race is an imperfect proxy. Discuss any medication changes with your prescriber.