Is ACTN3 useful for allergy?

No, ACTN3 is not useful for allergy. This gene encodes α-actinin-3, a protein found only in fast-twitch muscle fibers, and is associated with sprint and power performance. There is no scientifically established link between ACTN3 variants and allergic conditions such as hay fever, asthma, or food allergies. Claims that ACTN3 is relevant for allergy lack evidence and should be considered marketing or misunderstanding. For allergy testing, validated IgE antibody tests (e.g., specific IgE) ordered by an allergist are appropriate. Direct-to-consumer DNA tests for allergies often have weak or no clinical validation.