PLoS ONE (Jan 2013)

Haplotypes in IL-8 Gene Are Associated to Age-Related Macular Degeneration: A Case-Control Study.

  • Federico Ricci,
  • Giovanni Staurenghi,
  • Tiziana Lepre,
  • Filippo Missiroli,
  • Stefania Zampatti,
  • Raffaella Cascella,
  • Paola Borgiani,
  • Luigi Tonino Marsella,
  • Chiara Maria Eandi,
  • Andrea Cusumano,
  • Giuseppe Novelli,
  • Emiliano Giardina

DOI
https://doi.org/10.1371/journal.pone.0066978
Journal volume & issue
Vol. 8, no. 6
p. e66978

Abstract

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BACKGROUND:Age-related macular degeneration (AMD) is the main cause of blindness in the developed world. The etiology of AMD is multifactorial due to the interaction between genetic and environmental factors. IL-8 has a role in inflammation and angiogenesis; we report the genetic characterization of IL-8 allele architecture and evaluate the role of SNPs or haplotypes in the susceptibility to wet AMD, case-control study. METHODS:Case-control study including 721 AMD patients and 660 controls becoming from Italian population. Genotyping was carried out by Real Time-PCR. Differences in the frequencies were estimated by the chi-square test. Direct sequencing was carried out by capillary electrophoresis trough ABI3130xl. RESULTS:rs2227306 showed a p-value of 4.15*10(-5) and an Odds Ratio (OR) for T allele of 1.39 [1.19-1.62]. After these positive results, we sequenced the entire IL-8 regulatory and coding regions of 60 patients and 30 controls stratified for their genotype at rs2227306. We defined two different haplotypes involving rs4073 (A/T), rs2227306 (C/T), rs2227346 (C/T) and rs1126647 (A/T): A-T-T-T (p-value: 2.08*10(-9); OR: 1.68 [1.43-1.97]) and T-C-C-A (p-value: 7.07*10(-11); OR: 0.60 [0.51-0.70]). To further investigate a potential functional role of associated haplotypes, we performed an expression study on RNA extracted from whole blood of 75 donors to verify a possible direct correlation between haplotype and gene expression, failing to reveal significant differences. CONCLUSIONS:These results suggest a possible secondary role of IL-8 gene in the development of the disease. This paper outlines the importance of association between inflammation and AMD. Moreover IL-8 is a new susceptibility genomic biomarker of AMD.