Polymorphisms in Turkish population

Sections of Periodontology and Oral Biology, College of Dentistry, The Ohio State University Health Sciences Center, Columbus, OH 43218-2357, USA.

BACKGROUND: Neutrophil formylpeptide receptors (FPRs) play an important role in bacterial recognition and chemotaxis. Defective FPR1 expression and impaired polymorphonuclear leukocyte chemotaxis toward bacterial formylpeptides are associated with aggressive periodontitis (AgP). The objective of this study was to determine whether single nucleotide polymorphisms (SNPs) in FPR1 are associated with AgP. METHODS: Genomic DNA was isolated from blood samples obtained from African Americans (30 subjects with AgP and 33 healthy controls) and Turks (75 subjects with AgP and 63 healthy controls). A highly polymorphic fragment of the FPR1 gene was amplified by polymerase chain reaction and sequenced for analysis of SNPs. RESULTS: Five previously identified SNPs were detected in African Americans, whereas six were detected in Turkish subjects. The frequency of synonymous SNP c.348T>C was significantly higher in African Americans with AgP than in controls (P = 0.029). The 348T allele was significantly associated with AgP (P = 0.010). Seven of the subjects with AgP, but none of the controls, were homozygous for 348T. FPR1 haplotypes 348T.568A, 348T.576T, and 348T.568A.576T were significantly increased in African Americans with AgP (P <0.02). The Turkish population did not exhibit significant differences in FPR1 SNP frequencies between subjects with AgP and controls. CONCLUSIONS: FPR1 SNP c.348T>C is associated with AgP in African Americans. Individuals who are homozygous for 348T may have an increased risk for developing this disorder.

Department of Oral Biology and Center for Craniofacial and Dental Genetics, School of Dental Medicine, University of Pittsburgh, Pittsbergh, PA 15261, USA. arv11@dental.pitt.edu

Recently, the IRF6 contribution that was reported for Van der Woude syndrome and non-syndromic oral clefts was extended to isolated tooth agenesis. Here we report the first study that tries to replicate this finding and we provide further evidence that IRF6 contributes to isolated tooth agenesis. Fifty-two sporadic tooth agenesis cases and their parents were studied. DNA samples were obtained from whole blood or saliva samples. Genotyping was performed by TaqMan assays. Linkage disequilibrium analysis and transmission distortion of the marker alleles were performed. A haplotype involving the most 5′IRF6 markers was associated with sporadic tooth agenesis (p=0.006). An association could still be seen when only cases with at least one missing incisor (p=0.01) and cases with at least one missing premolar (p=0.004) were included in the analysis.