Cytokine gene polymorphisms and Alzheimer's disease in Brazil.

BACKGROUND

Single-nucleotide polymorphisms in genes encoding immunological mediators can affect the biological activity of these molecules by regulating transcription, translation, or secretion, modulating the genetic risk of inflammatory damage in Alzheimer's disease (AD). Nonetheless, the Brazilian contingent is highly admixed, and few association trials performed herein with AD patients have considered genetic ancestry estimates as co-variables when investigating markers for this complex trait.

METHODS

We analyzed polymorphisms in 10 inflammatory genes and compared the genotype distribution across outpatients with late-onset AD and noncognitively impaired subjects from Midwest Brazil under a strict criterion, and controlling for ancestry heritage and ApoE genotype.

RESULTS

Our findings show an almost 40% lower chance of AD (p = 0.004) among homozygotes of the IL10 -1082A allele (rs1800896). Dichotomization to ApoE and mean ancestry levels did not affect protection, except among those with greater European or minor African heritage.

CONCLUSION

The IL10 locus seems to affect the onset of AD in a context sensitive to the genetic ancestry of Brazilian older adults.