%0 Journal Article
%T Interleukin-1 Two-Locus Haplotype Is Strongly Associated with Severe Chronic Periodontitis among Yemenis
%A Nezar Noor Al-hebshi
%A Amat-alrahman Ahmed Shamsan
%A Mohammed Sultan Al-ak'hali
%J Molecular Biology International
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/231309
%X Aim. To assess IL-1A C[£¿889]T and IL-1B C[3954]T genotypes as well as haplotypes in relation to sever chronic periodontitis (SCP) among Yemenis. Materials and Methods. 40 cases with SCP and 40 sex- and age-matched controls were included; all were nonsmokers and free of systemic diseases. Genotyping at each locus was performed using an established PCR-RFLP assay. The Haploview and SimHap software were used to assess data for Hardy-Weinberg's equilibrium (HWE) and linkage disequilibrium (LD) and to obtain subject-level haplotypes. Multiple logistic regression was used to seek for associations in dominant, additive, and recessive models. Results. Mean plaque index (MPI) showed the strongest association with SCP ( ). A significant LD was observed in the cases ( and ). The genotype at each locus showed significant association with SCP in the recessive model (TT versus ) even after adjustment for MPI ( & 461, resp.). The C-T haplotype conferred protection against SCP in a dominant manner ( ). On the other hand, the T-T haplotype in double dose (recessive model) showed strong association with CP ( ). Conclusions. IL-1 two-locus haplotype is associated with SCP in Yemenis. Haplotype-based analysis may be more suited for use in genetic association studies of periodontitis. 1. Introduction Chronic periodontitis is currently viewed as an immunologically mediated destruction of tooth supporting tissues, the periodontium, provoked by specific pathogenic bacterial consortia in subgingival biofilm [1]. However, the occurrence, extent, and severity of the destructive process are dependent on the individual¡¯s susceptibility to the disease, which is in turn influenced by risk factors independent of the microbial challenge [2]. Environmental factors, such as cigarette smoking, and systemic diseases, such as diabetes, are well-established, classical examples of such risk modifiers [3]. Lately, the role of genetics in defining host susceptibility to chronic periodontitis has drawn much attention. Initial evidence for a significant genetic element in the pathogenesis of periodontitis came from twin- and family studies, in which chronic periodontitis was shown to have around 50% heritability [4, 5]. Since then, many genes, such as the cytokine gene family, pattern-recognition receptor genes and the vitamin D receptor gene, have been explored for allelic variants that may be associated with chronic as well as aggressive periodontitis [6]. Because some cytokines, particularly the IL-1 and TNF-A proteins, are strongly implicated in the pathogenesis of chronic periodontitis [7],
%U http://www.hindawi.com/journals/mbi/2012/231309/