Analysis of polymorphisms in the lactotransferrin gene promoter and dental caries

The association between MMP-13 rs478927 gene polymorphism and dental caries susceptibility in children with mixed dentition from Birjand, Iran: A case-control study

Background and Aims

Gene polymorphisms are responsible for at least part of the variation in caries susceptibility despite similar environmental factors. Genes involved in enamel formation like matrix metalloproteinase-13 (MMP-13) may participate in caries process. The aim was to investigate the association between MMP-13 rs478927 polymorphism and caries susceptibility in 6-years-old children from Birjand, Iran.

Methods

Six-years old children from Birjand, Iran, participated in this study. The total decayed, missing, and filled teeth were calculated and defined as caries index (CI). Based on this CI, two groups of high-caries (case) and low-caries (control) were taken into account. Saliva samples were collected and DNA was extracted. The allele and genotypes of MMP-13 rs478927 polymorphism were determined by tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) method. p Value was significant if p < 0.05.

Results

Three hundred sixty-seven children consisted of 186 low-caries children and 181 high-caries children were included in this study. The mean CI was 6.02 ± 0.81. There was no significant association between high and low-caries groups based on socioeconomic status, eating sweet snacks, parents' susceptibility to dental caries, duration of breastfeeding, and the brushing habit (p > 0.05). There wasn't any significant association between genotype distribution of MMP-13 rs478927 polymorphism and CI groups (p = 0.924). This polymorphism was associated with increased caries susceptibility under all genetic models but this effect was not significant (p > 0.05).

Conclusion

The MMP-13 rs478927 gene polymorphism was not significantly associated with dental caries susceptibility in Birjandi children with mixed dentition. It is recommended to conduct studies on children of different dentitions to better understand the role of this polymorphism on caries susceptibility in primary and permanent teeth of children.

Genes and single nucleotide polymorphisms in the pathway of saliva and dental caries: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to investigate the influence of single nucleotide polymorphisms (SNPs), related to genes in salivary composition and flow, on dental caries experience. Sixteen studies were included in the systematic review and ten in the meta-analysis. Forty-four SNPS, covering four genes (CA6, AQP2, AQP5, and MUC5B) were identified. Most of the SNPs were not associated with caries in meta-analysis. Homozygous TT genotype of the SNP CA6 rs17032907(C/T) was associated with caries [OR = 3.23(1.39-7.49)]. The pool effect of the SNPs assessed in AQP5 was associated with a reduction in the likelihood of caries [OR = 0.75(0.59-0.95)]. Considering all SNPs of salivary composition and flow, the effect allele was associated with a 75% increase in the likelihood of caries [OR = 1.75(1.06-2.89)] in the homozygous genotype. The present findings showed that the genes in salivary composition and flow can play an important role in dental caries experience.

Genetic Aspects of Dental Erosive Wear and Dental Caries

Objectives

The present review aims to give an overview of the literature focusing on novel genetic aspects of dental erosion and dental caries. Once the tooth erupts into the oral cavity, the regenerative capability of enamel is fundamentally limited due to the loss of dental epithelium during eruption. The susceptibility or resistance to dental erosion and caries is presumably a result of environmental, phenotypic, and/or genetic influence. Even though it is evident that individuals frequently exposing their teeth to acid and sugar are at high risk of developing dental erosion and caries, the findings exclusively based on these factors are elusive. Data resources and study selection. The present review was based on data collected from the National Library of Medicine database with different combinations of the following terms: "tooth," "dental," "dentin," "enamel," "erosion," "erosive wear," "caries," "decay," "gene," and "genetic." A total of forty-six studies met the inclusion criteria. Data were extracted by one reviewer and verified by another.

Conclusion

The high prevalence of erosion and caries among certain groups, and observations that not all individuals appearing to be at risk develop these lesions, has sparked research on identifying genetic effects to these conditions. A connection of genome-wide and candidate gene studies has increased considerably in the literature. This review reveals largely varying success among studies, demonstrating the difficulties of developing the study with adequate sample sizes and durable phenotype definitions that permit enough statistical power to identify genetic contributors.

The association between genetic polymorphisms in matrix metalloproteinases and caries experience

OBJECTIVES

The variation in the caries susceptibility while environmental factors are similar indicates that the effect of individual factors such as genetics on caries process and tooth development should be revealed. The aim of this study was to evaluate the association between genetic polymorphisms in MMP13 (rs2252070) and MMP20 (rs1784418) with caries experience.

MATERIALS AND METHODS

A cross-sectional study was conducted on 200 subjects aged 6 to 14 years. Demographic data, data on oral health habits were obtained through the statements of guardian of the individuals, caries data was collected by clinical examination. Unstimulated whole saliva was collected to extract the genomic DNA. Genotyping of the selected polymorphisms was carried out by real-time PCR. Allele and genotype frequencies were compared between different subgroups considering caries experience. Data were analyzed using SPSS 16.0 by chi-square test and logistic regression analysis.

RESULTS

Allele distribution of MMP13 was different between caries-affected and caries-free subjects. MMP13 A allele increased the caries risk (p=0.005, OR=1.84, 95% CI 1.20-2.82). Allele and genotype distribution of the polymorphism in MMP20 were not associated with caries experience (p>0.05).

CONCLUSIONS

It is concluded that the genetic variation in MMP13 was associated with the caries experience in selected subjects in Turkey.

CLINICAL RELEVANCE

The knowledge regarding association between the MMP genes and caries experience, might benefit the clinical practice, improving caries-preventive and caries-therapeutic approaches.

Genes and SNPs in the pathway of immune response and caries risk: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to pool the data on Single Nucleotide Polymorphisms (SNPs) in immune response genes associated with dental caries. Nineteen studies were included in the review and 18 in the meta-analysis. Twenty-two SNPs were evaluated, which are linked to six different genes (MBL2, LFT, MASP2, DEFB1, FCN2 and MUC5B). Most SNPs (81.8%) are related to the possible functional impact on protein coding. The MBL2 gene was associated with caries experience in the analysis of the homozygote (OR = 2.12 CI95%[1.12-3.99]) and heterozygote (OR = 2.22 CI95%[1.44-3.44]) genotypes. The MUC5B gene was associated according to an analysis of the heterozygous genotype (OR = 1.83 CI95%[1.08-3.09]). Thus, SNPs related to immune response genes are linked to the phenotype of caries experience. Although the meta-analysis showed that the genes MBL2 and MUC5B were associated with caries, these results should be interpreted with caution due to the quality of the evidence.

Lack of associations between lactoferrin (LTF) and mannose-binding lectin 2 (MBL2) gene polymorphism and dental caries susceptibility

Objective

With the development of human genomics, the genetic factors associated with dental caries have receiving increasing attention. This study was performed to evaluate the relationship between lactoferrin (LTF) and mannose-binding lectin 2 (MBL2) gene single nucleotide polymorphisms (SNPs) and dental caries susceptibility in Chinese children.

Methods

This prospective case–control study included 360 unrelated children (aged 12–15 years) who received oral health examinations and questionnaire surveys. The children were divided into two groups by counting the numbers of decayed, missing, and filled teeth (DMFT/dmft): case group (n = 162, DMFT/dmft ≥ 1) and control group (n = 198, DMFT/dmft = 0); non-invasive saliva samples were collected to extract genomic DNA. Six SNPs (rs2073495C/G, rs1042073C/T, rs10865941C/T, and rs1126477A/G in LTF; rs7096206C/G and rs7095891G/A in MBL2) were tested by mass spectrometry.

Results

The study included 360 individuals with (85 boys and 77 girls) and without a history of caries (96 boys and 102 girls). There were no statistically significant differences in alleles and genotypes among the six SNPs between the two groups.

Conclusion

There is no evidence that polymorphisms of LTF and MBL2 genes are associated with dental caries susceptibility in populations from northwest China; further confirmation is needed with larger sample sizes.

The association between genetic variants in lactotransferrin and dental caries: a meta- and gene-based analysis

BACKGROUND

The pathogenesis of dental caries remains unclear, with increasing evidence suggesting that genetic susceptibility plays an essential role. Previous studies have reported the association between genetic polymorphisms in lactotransferrin (LTF) and the risk of dental caries with inconsistent results.

METHODS

A systematic literature search of the PubMed, Cochrane Library, HuGE and Google Scholar databases was performed by two authors independently for papers published before December 5, 2019 on the association between genetic variants in LTF and the risk of dental caries. We adopted the subsequent inclusion criteria to assess study eligibility: 1) The studies were based on human subjects; 2) the presence of dental caries should be screened for in both the case group and the control group; and 3) genotype data on variants in LTF were available in both the case group and the control group. We calculated odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) by using random-effects models to assess the association of genetic variants in LTF with the risk of dental caries. We also performed a gene-based analysis to explore the joint association of multiple genetic variants in LTF with the risk of dental caries.

RESULTS

Our systematic literature search identified six relevant papers for analysis. We found no significant association between rs1126478 and the risk of dental caries when meta-analysing the genotype distribution between subjects with dental caries and those without dental caries (additive model: OR = 1.41; 95% CI = 0.98-2.02; P = 0.065). However, further analysis indicated that rs1126478 was associated with dental risk in subjects who had moderate or severe dental caries compared to those without dental caries (P < 0.0001). The gene-based analysis indicated that multiple genetic variants in LTF were jointly associated with the risk of dental caries (P = 0.002).

CONCLUSIONS

The present meta-analysis revealed some evidence of the association between rs1126478 and dental caries and that multiple genetic variants in LTF are jointly associated with the risk of dental caries. Our findings need to be validated by larger studies that adjust for important confounding factors for the risk of dental caries.

Application of Antibiotics/Antimicrobial Agents on Dental Caries

Dental caries is the most common oral disease. The bacteriological aetiology of dental caries promotes the use of antibiotics or antimicrobial agents to prevent this type of oral infectious disease. Antibiotics have been developed for more than 80 years since Fleming discovered penicillin in 1928, and systemic antibiotics have been used to treat dental caries for a long time. However, new types of antimicrobial agents have been developed to fight against dental caries. The purpose of this review is to focus on the application of systemic antibiotics and other antimicrobial agents with respect to their clinical use to date, including the history of their development, and their side effects, uses, structure types, and molecular mechanisms to promote a better understanding of the importance of microbial interactions in dental plaque and combinational treatments.

Dental caries: Genetic and protein interactions

OBJECTIVE

To present a genetic and protein interaction analysis associated with dental caries.

MATERIAL AND METHODS

The first step was to conduct a systematic literature review (SLR) through an electronic database search. Case-controls that reported associations between genes and dental caries were the main type of study design used as inclusion criteria, retrieved from the PubMed and the Virtual Health Library databases, comprising the chronological range from 1982 to 2017. The SLR was guided by PRISMA protocol and the methodological quality of the studies was established through Newcastle-Ottawa Scale (NOS). In the second step, the String Protein Interaction (SPI) approach was used to analyze protein interaction (by esyN software) and also the Ingenuity Pathway Analysis (IPA) to check biological pathways associated with dental caries genes.

RESULTS

A total of 51 articles were included to perform this SLR, describing a number of 27 genes associated with dental caries development. At the genetic level, 23 genes have at least one other gene with which they interact. The genes TUFT1, VDR, TFIP11, LTF, HLA-DRB1, MMP2, MMP3 and MUC5B were shown to be connected in interactive networks by at least 10 other genes.

CONCLUSION

It is essential to apprehend the multifactorial pattern of inheritance in human disease. This study presents pathways which may be directly correlated with several dental caries phenotype and this contributes to a better understanding of this disease, opening up a wider range of biotechnology options for its effective control in the future.

Host genetics role in the pathogenesis of periodontal disease and caries

BACKGROUND

This study aimed to produce the latest summary of the evidence for association of host genetic variants contributing to both periodontal diseases and caries.

MATERIALS AND METHODS

Two systematic searches of the literature were conducted in Ovid Medline, Embase, LILACS and Cochrane Library for large candidate gene studies (CGS), systematic reviews and genome-wide association studies reporting data on host genetic variants and presence of periodontal disease and caries.

RESULTS

A total of 124 studies were included in the review (59 for the periodontitis outcome and 65 for the caries outcome), from an initial search of 15,487 titles. Gene variants associated with periodontitis were categorized based on strength of evidence and then compared with gene variants associated with caries. Several gene variants showed moderate to strong evidence of association with periodontitis, although none of them had also been associated with the caries trait.

CONCLUSIONS

Despite some potential aetiopathogenic similarities between periodontitis and caries, no genetic variants to date have clearly been associated with both diseases. Further studies or comparisons across studies with large sample size and clear phenotype definition could shed light into possible shared genetic risk factors for caries and periodontitis.

Polymorphisms in Nonamelogenin Enamel Matrix Genes Are Associated with Dental Fluorosis

The aim of this study was to evaluate whether genetic polymorphisms in AMELX, AMBN, ENAM, TFIP11, and TUFT1 genes are associated with dental fluorosis (DF). A total of 1,017 children from 2 Brazilian cohorts were evaluated. These populations lived in cities with fluoridation of public water supplies. DF was assessed in erupted permanent teeth using the modified Dean index. The polymorphisms rs946252, rs12640848, rs4694075, rs5997096, and rs4970957 were analyzed by real-time PCR from genomic DNA. Associations between DF, genotype, and allele distribution were evaluated using the χ2 test, with an alpha of 5%. The polymorphisms rs4694075, rs5997096, and rs4970957 in AMBN, TFIP11, and TUFT1 were associated with DF (p < 0.05). In conclusion, enamel matrix genes are associated with DF.

Single Nucleotide Polymorphism in the Aetiology of Caries: Systematic Literature Review

Recent progress in the field of molecular biology and techniques of DNA sequence analysis allowed determining the meaning of hereditary factors of many common human diseases. Studies of genetic mechanisms in the aetiology of caries encompass, primarily, 4 main groups of genes responsible for (1) the development of enamel, (2) formation and composition of saliva, (3) immunological responses, and (4) carbohydrate metabolism. The aim of this study was to present current knowledge about the influence of single nucleotide polymorphism (SNP) genetic variants on the occurrence of dental caries. PubMed/Medline, Embase, and Cochrane Library databases were searched for papers on the influence of genetic factors connected with SNP on the occurrence of dental caries in children, teenagers, and adults. Thirty original papers written in English were included in this review. Study groups ranged from 30 to 13,000 subjects. SNPs were observed in 30 genes. Results of the majority of studies confirm the participation of hereditary factors in the aetiology of caries. Three genes, AMELX, AQP5, and ESRRB, have the most promising evidence based on multiple replications and data, supporting a role of these genes in caries. The review of the literature proves that SNP is linked with the aetiology of dental caries.

Genes Involved in the Enamel Development Are Associated with Calcium and Phosphorus Level in Saliva

Saliva components play a crucial role in the integrity of the dental enamel and in caries susceptibility. The saliva characteristics are controlled by many factors, including genetic factors. Therefore, this study aimed to evaluate the association between the genetic variations in genes expressed in enamel development with calcium and phosphorus levels in saliva. We collected 276 unrelated 12-year-old children from private and public schools. Saliva was collected for DNA extraction from oral cells and for measurement of calcium and phosphorus. Inductively coupled plasma-mass spectrometry determined calcium and phosphorus levels in whole saliva. Fifteen genetic variations in 9 genes were analyzed. The genotype was determined by real-time polymerase chain reactions. Data were analyzed using Plink with an alpha of 5%. Genetic variations in AMELX, AMNB and ESRRB were associated with the calcium level in saliva (p < 0.05). A borderline association was observed in ENAM allele distribution shown with phosphate level in saliva (p = 0.049). In conclusion, our results are the first to report that genetic variations contribute to calcium and phosphorus levels in saliva.

Association study for the role of Matrix metalloproteinases 2 and 3 gene polymorphisms in dental caries susceptibility

OBJECTIVE

Various exogenous and endogenous risk factors have been described as contributing to dental caries susceptibility. In the last decade it has been established that both pro and active forms of host derived Matrix metalloproteinases (MMPs) are present in the oral cavity. MMPs role in caries development has been hypothesized. The aim of this study was to analyse MMP2 (rs2287074) and MMP3 (rs679620) single nucleotide polymorphisms (SNPs) and their role in caries susceptibility.

DESIGN

The two SNPs were analysed by PCR- restriction fragment length polymorphism (RFLP) in a sample of 102 ethnic Bulgarian volunteers (42 males and 60 females), all students in Sofia Medical University.

RESULTS

Statistical analysis of the MMP2 SNP showed significant differences for the genotype frequencies between the caries free (CF, DMFT=0) and low caries experience (LCE, DMFT≤5) groups. Analysis for the non-synonymous MMP3 SNP found significant differences between both CF vs caries experience groups (LCE+ high caries experience (HCE, DMFT≥5)) and LCE vs HCE groups. The presence of allele G decreased the risk of HCE about 4 times.

CONCLUSIONS

MMP2 and MMP3 genes are likely to be involved in caries susceptibility in our population. However, as dental caries is a multifactorial disorder and several genes are likely to have influence on it, it is reasonable to expect that SNPs, even those proven to be functional like rs679620, potentially play a significant, but not major role in the disease outcome.

Lactotransferrin Gene Polymorphism Associated with Caries Experience

Dental caries is a common multifactorial disease, resulting from the interaction of biofilm, cariogenic diet and host response over time. Lactotransferrin (LTF) is a main salivary glycoprotein, which modulates the host immune-inflammatory and antibacterial response. Although a genetic component for caries outcome has been identified, little is known over the genetic aspects underlying its susceptibility. Thus, the aim of this study was to investigate the association between LTF polymorphisms and caries susceptibility. Six hundred seventy seven 12-year-old students were selected: 346 with (DMFT ≥ 1) and 331 without caries experience (DMFT = 0). Also, individuals concentrating higher levels of disease (polarization group, DMFT ≥ 2, n = 253) were tested against those with DMFT ≤ 1 (n = 424). Along with clinical parameters, three representative LTF tag SNPs (rs6441989, rs2073495, rs11716497) were genotyped and the results were evaluated using univariate and multivariate analyses. Allele A for tag SNP rs6441989 was found to be significantly less frequent in the polarization group, conferring a protective effect against caries experience [AA + AG × GG (OR: 0.710, 95% CI: 0.514-0.980, p = 0.045)], and remained significantly associated with caries protection in the presence of gingivitis (p = 0.020) and plaque (p = 0.035). These results might contribute to the understanding of the genetic control of caries susceptibility in humans.

Association of sweet taste receptor gene polymorphisms with dental caries experience in school children

Sweet taste is a powerful factor influencing food acceptance. The peripheral taste response to sugar is mediated by the TAS1R2/TAS1R3 taste receptors. The aim of the study was to determine the relationship between TAS1R2 (rs35874116 or rs9701796) and/or TAS1R3 (rs307355) single nucleotide polymorphisms with dental caries experience in schoolchildren. A total of 184 schoolchildren aged between 7 and 12 years (101 girls, 83 boys) were included in the study. Genomic DNA was extracted from saliva samples and the genotypes were identified by qPCR. The genotype frequencies were as follows: 6.6% for homozygous wild type, 41.8% for heterozygous and 51.6% for homozygous polymorphic genotype carriers of TAS1R2 gene rs35874116; 27.8% for heterozygous and 72.2% for homozygous polymorphic genotype carriers of TAS1R2 gene rs9701796, and 83.1% for homozygous wild type and 16.9% for heterozygous genotype carriers of TAS1R3 gene rs307355 polymorphism. A significant association was observed between total caries experience (dft + DMFT - decayed filled primary teeth + decayed, missing and filled permanent teeth) and TAS1R2 rs35874116 (p = 0.008) and TAS1R3 rs307355 (p = 0.04) gene polymorphisms but not for TAS1R2 gene rs9701796 polymorphism. TAS1R3 gene rs307355 polymorphism has been found to be an independent risk factor for dental caries experience by logistic regression analysis and to have increased the risk of caries. Moderate caries experience (4-7 caries) was found to be associated with TAS1R3 rs307355 heterozygous genotype, whereas high-risk caries experience (>8 caries) was found to be associated with TAS1R2 rs35874116 homozygous polymorphic genotype.

Early childhood caries is associated with genetic variants in enamel formation and immune response genes

Early childhood caries (ECC) is a chronic, infectious disease that affects the primary dentition of young children. It is the result of an imbalance of risk factors and protective factors that influence the disease. The aim of this study was to assess genetic and environmental factors that may contribute to ECC. Two hundred and fifty-nine unrelated children were evaluated using a cross-sectional design. Data on oral habits were obtained through a questionnaire, and caries experience data were collected by clinical examination. Twenty-three markers in 10 genes were studied. Genotyping of the selected polymorphisms was carried out by real-time PCR. Regression analyses were performed comparing individuals with and without caries experience. Of 259 subjects, 123 were caries free. The genotype TT in ALOX15 (rs7217186) was a risk factor for ECC, whereas the genotypes GG in ENAM (rs1264848), AG and GG in KLK4 (rs198968), CT in LTF (rs4547741), and GG in TUFT1 (rs3790506) were protective for EEC. In conclusion, environmental factors and gene interactions can act as protective or risk factors for ECC. These factors together contribute to the presence and severity of the disease.

Caries: review of human genetics research

The NIH Consensus Development Program released a statement in 2001 (http://consensus.nih.gov/2001/2001DentalCaries115html.htm) and listed six major clinical caries research directions. One of these directions was the need for genetic studies to identify genes and genetic markers of diagnostic, prognostic and therapeutic value. This last decade has seen a steep increase in studies investigating the presence of genetic factors influencing individual susceptibility to caries. This review revisits recent caries human genetic studies and provides a perspective for future studies in order to fulfil their promise of revolutionizing our understanding of and the standard of care for the most prevalent bacteria-mediated non-contagious disease in the world.

Genetic Association of MPPED2 and ACTN2 with Dental Caries

The first genome-wide association study of dental caries focused on primary teeth in children aged 3 to 12 yr and nominated several novel genes: ACTN2, EDARADD, EPHA7, LPO, MPPED2, MTR, and ZMPSTE24. Here we interrogated 156 single-nucleotide polymorphisms (SNPs) within these candidate genes for evidence of association with dental caries experience in 13 race- and age-stratified samples from 6 independent studies (n = 3600). Analysis was performed separately for each sample, and results were combined across samples via meta-analysis. MPPED2 was significantly associated with caries via meta-analysis across the 5 childhood samples, with 4 SNPs showing significant associations after gene-wise adjustment for multiple comparisons (p < .0026). These results corroborate the previous genome-wide association study, although the functional role of MPPED2 in caries etiology remains unknown. ACTN2 also showed significant association via meta-analysis across childhood samples (p = .0014). Moreover, in adults, genetic association was observed for ACTN2 SNPs in individual samples (p < .0025), but no single SNP was significant via meta-analysis across all 8 adult samples. Given its compelling biological role in organizing ameloblasts during amelogenesis, this study strengthens the hypothesis that ACTN2 influences caries risk. Results for the other candidate genes neither proved nor precluded their associations with dental caries.

Multi-dimensional prioritization of dental caries candidate genes and its enriched dense network modules

A number of genetic studies have suggested numerous susceptibility genes for dental caries over the past decade with few definite conclusions. The rapid accumulation of relevant information, along with the complex architecture of the disease, provides a challenging but also unique opportunity to review and integrate the heterogeneous data for follow-up validation and exploration. In this study, we collected and curated candidate genes from four major categories: association studies, linkage scans, gene expression analyses, and literature mining. Candidate genes were prioritized according to the magnitude of evidence related to dental caries. We then searched for dense modules enriched with the prioritized candidate genes through their protein-protein interactions (PPIs). We identified 23 modules comprising of 53 genes. Functional analyses of these 53 genes revealed three major clusters: cytokine network relevant genes, matrix metalloproteinases (MMPs) family, and transforming growth factor-beta (TGF-β) family, all of which have been previously implicated to play important roles in tooth development and carious lesions. Through our extensive data collection and an integrative application of gene prioritization and PPI network analyses, we built a dental caries-specific sub-network for the first time. Our study provided insights into the molecular mechanisms underlying dental caries. The framework we proposed in this work can be applied to other complex diseases.

Role of TRAV locus in low caries experience

Caries is the most common chronic, multifactorial disease in the world today; and little is still known about the genetic factors influencing susceptibility. Our previous genome-wide linkage scan has identified five loci related to caries susceptibility: 5q13.3, 13q31.1, 14q11.2, 14q 24.3, and Xq27. In the present study, we fine mapped the 14q11.2 locus to identify genetic contributors to caries susceptibility. Four hundred seventy-seven subjects from 72 pedigrees with similar cultural and behavioral habits and limited access to dental care living in the Philippines were studied. An additional 387 DNA samples from unrelated individuals were used to determine allele frequencies. For replication purposes, a total of 1,446 independent subjects from four different populations were analyzed based on their caries experience (low versus high). Forty-eight markers in 14q11.2 were genotyped using TaqMan chemistry. Transmission disequilibrium test was used to detect over transmission of alleles in the Filipino families, and Chi-square, Fisher's exact and logistic regression were used to test for association between low caries experience and variant alleles in the replication data sets. We finally assessed the mRNA expression of TRAV4 in the saliva of 143 study subjects. In the Filipino families, statistically significant associations were found between low caries experience and markers in TRAV4. We were able to replicate these results in the populations studied that were characteristically from underserved areas. Direct sequencing of 22 subjects carrying the associated alleles detects one missense mutation (Y30R) that is predicted to be probably damaging. Finally, we observed higher expression in children and teenagers with low caries experience, correlating with specific alleles in TRAV4. Our results suggest that TRAV4 may have a role in protecting against caries.

Fine-mapping of 5q12.1-13.3 unveils new genetic contributors to caries

Caries is a multifactorial disease and little is still known about the host genetic factors influencing susceptibility. Our previous genome-wide linkage scan has identified the interval 5q12.1-5q13.3 as linked to low caries susceptibility in Filipino families. Here we fine-mapped this region in order to identify genetic contributors to caries susceptibility. Four hundred and seventy-seven subjects from 72 pedigrees with similar cultural and behavioral habits and limited access to dental care living in the Philippines were studied. DMFT scores and genotype data of 75 single-nucleotide polymorphisms were evaluated in the Filipino families with the Family-Based Association Test. For replication purposes, a total 1,467 independent subjects from five different populations were analyzed in a case-control format. In the Filipino cohort, statistically significant and borderline associations were found between low caries experience and four genes spanning 13 million base pairs (PART1, ZSWIM6, CCNB1, and BTF3). We were able to replicate these results in some of the populations studied. We detected PART1 and BTF3 expression in whole saliva, and the expression of BTF3 was associated with caries experience. Our results suggest BTF3 may have a functional role in protecting against caries.

Enamel formation genes influence enamel microhardness before and after cariogenic challenge

There is evidence for a genetic component in caries susceptibility, and studies in humans have suggested that variation in enamel formation genes may contribute to caries. For the present study, we used DNA samples collected from 1,831 individuals from various population data sets. Single nucleotide polymorphism markers were genotyped in selected genes (ameloblastin, amelogenin, enamelin, tuftelin, and tuftelin interacting protein 11) that influence enamel formation. Allele and genotype frequencies were compared between groups with distinct caries experience. Associations with caries experience can be detected but they are not necessarily replicated in all population groups and the most expressive results was for a marker in AMELX (p=0.0007). To help interpret these results, we evaluated if enamel microhardness changes under simulated cariogenic challenges are associated with genetic variations in these same genes. After creating an artificial caries lesion, associations could be seen between genetic variation in TUFT1 (p=0.006) and TUIP11 (p=0.0006) with enamel microhardness. Our results suggest that the influence of genetic variation of enamel formation genes may influence the dynamic interactions between the enamel surface and the oral cavity.

Serum level of intercellular adhesion molecule-1 in children with malignant lymphoma

OBJECTIVE

To estimate the serum levels of soluble intercellular adhesion molecule-1 (s-ICAM-1) in children newly diagnosed with lymphoma and to correlate levels of s-ICAM-1 in lymphoma patients with clinical stage, pathological types, clinical and laboratory data and patient outcome.

SUBJECTS AND METHODS

Thirty-five children with newly-diagnosed malignant lymphoma (Non-Hodgkin's lymphoma, NHL: 23), Hodgkin's disease (HD: 12), and 8 apparently healthy subjects of matched age and sex taken as a control group were studied. For the patients and control group, the following tests were performed: complete blood count, and the following biochemical investigations: liver function tests, lactate dehydrogenase (LDH), and soluble ICAM-1 estimation using ELISA. In addition, for patients, pathological examination of lymph node biopsy for pathological grading, bone marrow aspiration and biopsy were done. Patients were observed for over 12 months or until death.

RESULTS

Serum ICAM-1 increased more in HD and NHL than in the control group (p < 0.000); also s-ICAM-1 increased in advanced stages and high-grade NHL (p < 0.008, 0.04, respectively). LDH levels were higher in patients compared to controls (p < 0.000). There was a positive correlation between high levels of s-ICAM-1 and increased levels of LDH in HD (r = 0.72, p < 0.008) and a positive correlation between high levels of s-ICAM-1 and increased ALT in NHL patients. A positive correlation between s-ICAM-1 levels and the presence of B symptoms in HD and NHL, and a positive correlation between elevated s-ICAM-1 levels and worse outcome in HD and NHL were detected.

CONCLUSIONS

The data indicate that in children with malignant lymphoma, high serum levels of ICAM-1 correlated with tumor aggressiveness, and quantification of s-ICAM-1 levels may identify a subgroup of children with worse prognosis. Therefore, detection of s-ICAM-1 levels in children with malignant lymphoma might represent an additional disease-associated marker for use in the clinical management of the patients.