In humans, a GRK5 sequence polymorphism at residue 41 (leucine rather than glutamine) that is most common in individuals with African ancestry leads to elevated GRK5-mediated desensitization of airway beta2-adrenergic receptors, a drug target in asthma.
The genetic variation in the GRK5 gene, specifically at position 41, where leucine replaces glutamine, is more common among individuals with African ancestry and leads to increased desensitization of airway beta2-adrenergic receptors, making them less responsive to asthma medications.