Tracing disease gene(s) in non-syndromic clefts of orofacial region: HLA haplotypic linkage by analyzing the microsatellite markers: MIB, C1_2_5, C1_4_1, and C1_2_A.

BACKGROUND: Cleft lip with or without cleft palate (CL/P) is the most frequent craniofacial malformation seen in man. The etiology of CL/P is complex involving both genetic and epigenetic (environmental) factors, and the genes play an almost deterministic role in the normal development of craniofacial structures. This study was aimed at ascertaining the association of HLA microsatellites in CL/P patients. MATERIALS AND METHODS: Case DNA was obtained from 76 patients (40M and 36 F, average age 7.8 years, range 1-16 years). Unaffected individuals from the same geographical area without population mixing included as controls (n=154, 76 M and 78 F, average age 8.2 years, range 2-17 years). All DNA samples were purified from peripheral blood by standard techniques. RESULTS: Four microsatellites were compared in this case-control study. C1_2_5 locus was the most polymorphic marker with 15 observed alleles while C1_4_1 had the least number of alleles. Three of the four markers viz MIB,C1_4_1 and C1_2_5 showed a significant association of microsatellite alleles with CL/P. Five alleles (MIB_326,332,350; C1_4_1 – 213 and C1_2_5-204) were seen with an increased frequency among the test samples, whereas two alleles (C1-4_1_217, and C1_2_5_196) had an increased frequency among the control samples. One allele (C1-4-1-209) had an increased frequency in patient group but was not observed in the controls. CONCLUSION: The role of HLA complex in the pathogenesis of CL/P is speculative and has not been established so far. The result of this study shows that a few alleles have an increased frequency of expression in the diseased group which suggests that these alleles may predispose the individuals to clefting. This finding may be beneficial to aid in early diagnosis and plan intervention strategies.

Transforming growth factor-β-1 polymorphisms are infrequent but exist at selected loci in oral submucous fibrosis.

Background : Oral submucous fibrosis (OSF) may be considered a collagen metabolic disorder resulting from areca-nut alkaloid exposure and individual variation in collagen metabolism. Due to the complexity of OSF pathogenesis, it is important to elucidate independent and interactive effects of polymorphisms of collagen-related genes on OSF risk. Materials and Methods : This study is focused on seven polymorphisms (SNPs) of transforming growth factor-beta-1 (TGF-beta-1) gene in patients with oral submucous fibrosis (OSF), belonging to south Indian ethnic extraction. The mean age at presentation was 43.9 years, range 23-72 years (n=50, M:F ratio, 2.6:1). DNA samples from 50 subjects of the same ethnic group and comparable demographic features who have had practiced the habit of areca-chewing of almost equal duration, but remained free of disease constituted the controls. All DNA samples were collected progressively and purified from peripheral blood employing standard protocols and tested for SNPs. They included two polymorphisms in the promoter region (C-509T and G-800A), three polymorphisms in exon-1 (Arg25Pro(G915C), Leu10Pro(T869C), Glu47Gly(A979G) and two in 5 ͲUTR regions (C→T(rs13306708) and G→A (rs9282871). The extracted DNA samples along with the primers underwent PCR amplification and the genotypic and allelic frequencies were calculated. All calculations were performed using the SPSS software. The PCR products were purified and subsequently sequenced using Flour S™ multi-imager system (Biorad). The sequenced data were analyzed using the BioEdit sequence analysis software. Results : Out of the seven polymorphisms analyzed, six such as two in the promoter region, three in exon-1 and one in 5¢UTR were found to have a " P" value above 0.05 and hence were not significant. The C→T transition (rs13306708) in the 5¢UTR region recorded a " P" value of 0.03 on comparison and hence was found to be significant. The allelic frequencies for this C→T transition in patients were 68.7% C and 31.2% T (27CC, 15CT, 8TT) and that in controls were 89.5% C and 10.4% T (42CC, 6CT, 2TT). Conclusions : The polymorphism in 5¢UTR C-T in TGF beta 1 gene has a significant association with OSF, being a prime determinant in the pro-angiogenic pathway which has got direct bearing with the pathophysiology of the disease. The proximity of this polymorphism to the transcription site and the associated risk involved is discussed.

Study of the patterns of periodontal destruction in smokers with chronic periodontitis.

Cigarette smoking is a well-established risk factor for periodontitis and carries an increased risk for loss of periodontal attachment as well as for bone loss. AIMS: The purpose of the study was to investigate the pattern of the intraoral distribution of periodontal destruction among cigarette smokers with periodontitis by assessing the periodontal probing depth (PPD) and clinical attachment level (CAL). MATERIALS AND METHODS: Thirty smokers with chronic periodontitis were enrolled in the study. PPD, CAL, plaque index (PI), and bleeding on probing (BOP) were measured. The data was pooled for the anterior sextant and the posterior sextant as well as for the facial and lingual surfaces. The degree of periodontal destruction was compared in these sextants. STATISTICAL ANALYSIS: Comparisons were made between maxillary anterior, maxillary posterior, mandibular anterior, and mandibular posterior using the one-way analysis of variance (ANOVA) test. When the overall ANOVA showed statistical significance, post hoc testing (Tukey-Kramer multiple comparisons test) was performed to explore the differences between any two groups. P -values < 0.05 were considered significant. RESULTS: The maxillary anterior sextant showed significantly higher PPD and CAL loss than the other sextants. Similarly, the maxillary palatal area showed higher probing depth and clinical attachment loss than the facial sites and the mandibular regions. CONCLUSIONS: From the results it can be concluded that there is variation in the periodontal tissue destruction in different areas of the oral cavity, with the maximum periodontal destruction in the maxillary palatal region. These observations emphasize the deleterious effects of smoking on the periodontal tissues.

Immunoglobulin concentration in gingival tissue of type 2 diabetic patients with periodontitis.

BACKGROUND: Diabetes mellitus is considered as a risk factor for the initiation and progression of periodontal disease. The diabetic patients often exhibit decreased immune response and increased susceptibility to infection. In the present study, a quantitative estimation of the gingival tissue immunoglobulin concentrations in diabetic and non diabetic subjects with periodontitis was assessed and compared with that of clinically healthy gingiva. METHOD: 40 gingival tissue samples obtained from 20 diabetic (Type 2) and 20 non-diabetic subjects were subjected to quantitative estimation of immunoglobulins G, A, and M. The data thus obtained were compared to the level of immunoglobulin found in clinically healthy gingiva. RESULTS: The IgG and IgA level in the tissues of both diabetic and non-diabetic subjects with periodontitis were found to be significantly higher than that of healthy subjects. The diabetic group also showed a significantly higher IgG and IgA levels compared to the non-diabetic group with periodontitis. CONCLUSION: These findings support the concept that the humoral immune response plays an important role in the pathogenesis of periodontal disease in diabetics. The significantly higher levels of immunoglobulin in the gingival tissues might be a protective mechanism against the increased bacterial challenge in diabetic subjects.