Genotypic and allelic distributions of rs2486668 in NSOFC cases and controls.

<p>Genotypic and allelic distributions of rs2486668 in NSOFC cases and controls.</p

Lack of Association between Missense Variants in <i>GRHL3</i> (rs2486668 and rs545809) and Susceptibility to Non-Syndromic Orofacial Clefts in a Han Chinese Population

<div><p>Background</p><p>Grainyhead-like-3 (<i>GRHL3</i>) was recently identified as the second gene that, when mutated, can leads to Van der Woude syndrome, which is characterized by orofacial clefts (OFC) and lower lip pits. In addition, a missense variant (rs41268753) in <i>GRHL3</i> confers risk for non-syndromic cleft palate cases of European ancestry. Together with interferon regulatory factor 6 (<i>IRF6</i>), <i>GRHL3</i> may be associated with the risk of NSOFC which awaits for being verified across different ethnic populations.</p><p>Objective</p><p>The aim of this study was to investigate the possible relationship between common functional variants in <i>GRHL3</i> and susceptibility to NSOFC, especially cleft palate cases, in a Han Chinese population, one of the ethnic groups with the highest birth prevalence of orofacial clefting.</p><p>Methods</p><p>Because the allele frequency for rs41268753 minor alleles was zero in our Chinese population, we selected functional single nucleotide polymorphisms (SNPs) spanning <i>GRHL3</i> with minor allele frequencies (MAFs) > 5% in the Han Chinese population. Two SNPs which meet the above criteria were then genotyped in a case-control cohort comprising 1145 individuals using the TaqMan 5′-exonuclease allelic discrimination assay.</p><p>Results</p><p>SNPs rs2486668 and rs545809 were used in this study. Overall genotype and allele distributions of both SNPs in general and stratified genotyping analyses revealed no statistically significant differences between cases and controls. Further logistic regression analyses using different genetic models failed to reveal any evidence that these markers influence risk to NSOFC.</p><p>Conclusions</p><p>The variant rs41268753 in <i>GRHL3</i> increases the risk for cleft palate in European population, but our findings failed to detect the link between two <i>GRHL3</i> SNPs (rs2486668 and rs545809) and risk to NSOFC in the Han Chinese cohort. Although the present study did not provide any evidence that common functional variants in <i>GRHL3</i> may contribute to NSOFC etiology in this Chinese population, further studies with a larger sample size, additional SNPs, and a more diverse ethnic cohort are still warranted.</p></div

Genotypic and allelic distributions of rs545809 in NSOFC cases and controls.

<p>Genotypic and allelic distributions of rs545809 in NSOFC cases and controls.</p

Functional analysis of genes that exhibited altered expression levels.

<p>Functional analysis of genes that exhibited altered expression levels.</p

Differentially expressed genes among these three groups were involved in the inflammation signal pathway.

<p>Red and blue represents the up- and down- regulated genes respectively.</p

Identification of the causative mutation in <i>EDA</i> gene.

<p>Arrows indicate the mutation site. The affected male patient and his mother harbored a frameshift mutation c.573–574insT.</p

<i>EDA</i> promoter’s methylation analysis of 23 carriers.

<p>(A) Pyrosequencing graphs of 2 samples, a hypermethylation carrier and a hypomethylation carrier. Peak heights are proportional to the number of identical residues incorporated. Percentage in pictures means allele frequency of each site. (B) The 95% CI for the 4 sites. The figures which refer to methyl-cytosine percent at that site are calculated as described in the text. (C) The methylation state of each carriers in the 4 sites. Red, white and blue refer to hypermethylation, normal and hypomethylation respectively.</p

Clinical phenotypes of family members in the Chinese pedigree.

<p>A: affected; C: carrier; F: female; M: male; NM: no missing; +: positive; number of ‘+’ symbols reflects the degree of these clinical features; -: negative; 13: Right maxillary canine; 23: Left maxillary canine.</p

The mutations and some selected clinical findings of twenty-three carriers.

a<p>E: Extracellular domain; F: Furin domain; C: Collagen domain; T: TNF homology domain.</p>b<p>Hyper: hypermethylation; Hypo: hypomethylation.</p>c<p>not examined.</p>*<p>unpublished data.</p

Relationship between methylated state and phenotype of XLHED carriers.

<p>Hypermethylated carriers are inclined to have more conical shaped tooth and nail dysplasia than hypomethylated group.</p