The association of EGF rs2237051 variant, serum EGF levels and generalized aggressive periodontitis: a preliminary study

New insights into the genetics of mandibular retrognathism: novel candidate genes

PURPOSE

Mandibular retrognathism (MR) is a common skeletal malocclusion in humans with a strong genetic component. Single nucleotide polymorphisms (SNPs) in genes encoding epidermal growth factor (EGF) and EGF receptor (EGFR) could be involved in the etiology of mandibular retrognathism. Therefore, in this study, we investigated whether SNPs in the genes encoding for EGF and EGFR are associated with MR in German teenagers.

METHODS

This nested case-control study evaluated German orthodontic patients, aged 10-18 years. DNA, which was isolated from buccal epithelial cells using two cytobrushes, was used for genotyping analysis and digital pretreatment lateral cephalograms were examined to calculate SNB and ANB. Patients with a retrognathic mandible (SNB < 78°) were included as cases, while patients with an orthognathic mandible (SNB = 78-82°) were included as controls. Four SNPs in the genes encoding for EGF and EGFR were chosen and genotyped using real-time PCR. Allele, genotype, and haplotype frequency were compared across groups (α = 5%).

RESULTS

Finally, 119 patients were included in this study (45 orthognathic mandible, 74 retrognathic mandible). The minor allele G in rs4444903 (EGF) was statistically more frequent in individuals with an orthognathic mandible (p = 0.008). The haplotype formed by the mutant alleles for rs4444903|rs2237051 (EGF; G|A) was statistically more frequent in the orthognathic mandible group (p = 0.007). The SNPs rs4444903 and rs2237051 in EGF, and rs2227983 in EGFR were statistically associated with a decreasing risk of developing a retrognathic mandible according to univariate and multivariate statistical analysis (p < 0.05).

CONCLUSION

SNPs in EGF (rs4444903 and rs2237051) and EGFR (rs2227983) were associated with MR in our German sample and could be genetic biomarkers for early and individualized diagnostic identification of retrognathic mandibular development by means of genetic screening tests.

Genetic association of the epidermal growth factor gene polymorphisms with peri-implantitis risk in Chinese population

Peri-implant disease is an inflammatory disease and is related to genetic heterogeneity. Considering the genetic association of epidermal growth factor (EGF) gene polymorphisms with the susceptibility of periodontitis, its genetic association with peri-implantitis risk in a Chinese Han population was explored. Three hundred individuals who underwent dental implants were recruited, and divided into healthy implant group and peri-implantitis group. The genotype and allele distribution of EGF gene rs2237051 and rs4444903 polymorphisms were analyzed via direct sequencing and the frequencies were compared between the two groups using chi-square test. No significant difference was detected for the clinical information between healthy implant group and peri-implantitis group, including lifestyle habits platform type and position, peri-implant phenotype, brushing time, dental floss, and mouth washing frequencies. Individuals with peri-implantitis had poor periodontal status. The GG genotype and G allele of rs2237051 showed significant increasing trend in peri-implantitis group compared with the healthy implant group. Compared with the AA genotype carriers, rs2237051 GG genotype carriers showed lower risk to suffer from peri-implantitis (OR = 0.236, 95%CI = 0.089–0.624), and possessed low values of gingival index, plaque index and calculus index, peri-implant pocket depth (PPD) and clinical attachment level (CAL). But there was no significant difference for the rs4444903 genotype distributions between the case and control groups. In summary, EGF rs2237051 polymorphism showed close association with the genetic background of peri-implantitis. Rs2237051 GG genotype and G allele might be protective factors for the onset of peri-implantitis.