Myths vs facts: CLOCK and allergy

The claim that the CLOCK gene directly causes allergies is a myth. CLOCK (Circadian Locomotor Output Cycles Kaput) regulates the internal circadian rhythm, which indirectly modulates immune function. Disrupted circadian rhythms—due to shift work, jet lag, or poor sleep—can alter the release of inflammatory mediators like histamine and cytokines, potentially worsening allergic symptoms in susceptible individuals. However, the effect is modest and not causal. Allergies are polygenic and strongly influenced by environmental factors such as pollen exposure, diet, and microbiome. A single CLOCK variant test has no validated clinical utility for allergy prediction or management. Evidence: mechanistic/moderate. Sources: none specific in provided context.