Disappearance of epidermal growth factor receptor is essential in the fusion of the nasal epithelium

Exploring polymorphisms in genes encoding growth factors associated with non-syndromic cleft lip with or without cleft palate and tooth agenesis

OBJECTIVE

To evaluate the association between non-syndromic cleft lip with or without cleft palate (NSCL±P) and tooth agenesis (TA), as well as the association of both conditions with polymorphisms in genes encoding growth factors.

METHODOLOGY

This cross-sectional study included children with NSCL±P and a control group of children without NSCL±P. Permanent teeth TA (excluding third molars) was evaluated using panoramic radiographs by a trained examiner. Only TA located outside the cleft was considered in the NSCL±P group. Genetic polymorphisms in Transforming Growth Factor Beta 1 (TGFB1)-rs1800470 and rs4803455-Transforming Growth Factor Beta Receptor 2 (TGFBR2)-rs3087465 and rs764522-Epidermal Growth Factor (EGF)-rs4444903 and rs2237051-and Epidermal Growth Factor Receptor (EGFR)-rs2227983- were genotyped by real-time PCR allele discrimination from buccal cell samples. Associations were tested by uni and multivariable Poisson regression models (5% significance level).

RESULTS

A total of 243 children-127 with NSCL±P (mean age = 8.80±2.14 years) and 116 without NSCL±P (mean age = 8.58±2.03 years) were included. TA was more frequent in the NSCL±P group (23.8%) than in the control group (6.2%) (p<0.01). The EGF rs2237051 was significantly associated with NSCL±P, independently of the other variables (PRa=1.41; p=0.042). Regarding TA, only the cleft presence was associated with a higher prevalence of TA regardless of different variables (PRa=3.70; p=0.001). There was no association between TA and the investigated genetic polymorphisms. When TA and NSCL±P were considered together, a borderline association was observed with rs1800470 in TGFB1 (p=0.06).

CONCLUSION

NSCL±P is associated with TA outside the cleft area. The EGF rs2237051 was associated with NSCL±P. Polymorphisms in genes encoding growth factors are not associated with TA.

Polymorphisms and dental age in non-syndromic cleft lip and palate: a cross-sectional study

BACKGROUND

Children with non-syndromic cleft lip with or without palate (CL ± P) may present alterations in dental development. The purpose of this cross-sectional study was to compare the dental age (DA) between children with and without CL ± P, and whether single nucleotide polymorphisms (SNPs) in genes encoding growth factors are associated with DA variations.

METHODS

Children aged between 5 and 14 years with and without CL ± P were recruited to participate in this study. DA was evaluated by calibrated examiners (kappa > 0.80) using the method proposed by Demirjian et al. (1973). Genomic DNA was extracted from buccal cells, and SNPs in Epidermal Growth Factor (EGF) - rs4444903 and rs2237051, Epidermal Growth Factor Receptor (EGFR) - rs2227983 -, Transforming Growth Factor Beta 1 (TGFB1) - rs1800470 and rs4803455 -, and Transforming Growth Factor Beta Receptor 2 (TGFBR2) - rs3087465 - were genotyped by real-time polymerase chain reactions using the TaqMan assay. The Student T-test was used to compare the variations in DA between the phenotypes "with CL ± P" and "without CL ± P", and the ANOVA two-way test was performed to compare the variations in DA among the genotypes (α = 0.05). A post-hoc analysis was performed using Bonferroni correction.

RESULTS

Two hundred and nine (n = 209) children (100 with CL ± P and 109 without CL ± P) with a mean chronological age of 8.66 years - standard deviation (SD) = 1.92 - were included. The group with CL ± P demonstrated a significantly delayed DA (mean=-0.23; SD = 0.71) compared to the group without CL ± P (mean=-0.01; SD = 0.88) (p = 0.049). Genotype distributions were in Hardy-Weinberg equilibrium. The SNP rs4803455 in TGFB1 was significantly associated with DA variations in children without CL ± P (p < 0.01). In the group with CL ± P, no significant differences in DA were observed among the genotypes.

CONCLUSION

Children with CL ± P presented delayed DA compared with children without CL ± P. The SNP rs4803455 in TGFB1 is associated with variations in DA in children without CL ± P.