Evaluation of human leukocyte N-formylpeptide receptor (FPR1) SNPs in aggressive periodontitis patients

Polymorphonuclear neutrophils (PMNs) are attracted to sites of infection by N-formylpeptide (fMLP) chemoattractants. The high-affinity fMLP receptor (FPR1) of phagocytic cells interacts with bacterial fMLP and mediates chemotaxis, degranulation, and superoxide production. These cellular functions are disrupted in PMN from aggressive periodontitis (AP) patients. Two FPR1 gene single nucteotide polymorphisms (SNPs), c.329T> C and c.378C> G, have been associated with a localized form of AP in African-American patients. To evaluate the generality of these SNPs in AP patients, we sequenced a 363 bp interval of the FPR1 gene in an ethnically diverse group of patients (n = 111) and controls (n = 115). Neither c.329T> C nor c.378C> G were detected in the 452 alleles sequenced. Six SNPs were identified including two located in the FPR1 second extracellular loop that were significantly associated with the AP phenotype in African-American patients (p.R190W, P = 0.0033; and p.N192K, P = 0.0018). These two SNPs show three predominant haplotypes, each associated with a different disease risk in African-Americans. These data do not support the hypothesis that the FPR1 SNPs c.329T> C and c.378C> G play an etiologic role in aggressive periodontitis, but do suggest that SNPs in the second extracellular loop may be etiologically important.