Resequencing of VAX1 in patients with nonsyndromic cleft lip with or without cleft palate.

BACKGROUND: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all congenital anomalies, and has a multifactorial etiology involving both environmental and genetic factors. Recent genome-wide association studies (GWAS) identified strong association between a locus on chromosome 10q25.3 and NSCL/P in European samples. One gene at 10q25.3, the ventral anterior homeobox 1 (VAX1) gene, is considered a strong candidate gene for craniofacial malformations. The purpose of the present study was to provide further evidence that VAX1 is the causal gene at the 10q25.3 locus through identification of an excess of rare mutations in patients with NSCL/P. METHODS: The 5'UTR, complete coding regions, and adjacent splice sites of the two known VAX1 isoforms were sequenced in 384 patients with NSCL/P and 384 controls of Central European descent. Observed variants were investigated with respect to familial cosegregation or de novo occurrence, and in silico analyses were performed to identify putative effects on the transcript or protein level. RESULTS: Eighteen single-base variants were found, 15 of them rare and previously unreported. In the long VAX1 isoform, predicted functionally relevant variants were observed more often in NSCL/P cases, although this difference was not significant (p = 0.17). Analysis of family members demonstrated incomplete cosegregation in most pedigrees. CONCLUSION: Our data do not support the hypothesis that highly penetrant rare variants in VAX1 are a cause of NSCL/P. To determine whether VAX1 is the causative gene at 10q25.3 further research, in particular into the biologic function of its long isoform, is warranted. Birth Defects Research (Part A), 2012.

Genetic risk factors for nonsyndromic cleft lip with or without cleft palate in a Mesoamerican population: Evidence for IRF6 and variants at 8q24 and 10q25.

INTRODUCTION: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all birth defects. NSCL/P has a multifactorial etiology that includes both genetic and environmental factors. The IRF6 gene and three further susceptibility loci at 8q24, 10q25, and 17q22, which were identified by a recent genome-wide association scan (GWAS), are confirmed genetic risk factors for NSCL/P in patients of European descent. METHODS: A case-control association study was performed to investigate whether these four risk loci contribute to NSCL/P in a Mesoamerican population using four single nucleotide polymorphisms to represent IRF6 and the three novel susceptibility loci. A total of 149 NSCL/P patients and 303 controls of Mayan origin were included. RESULTS: Single marker analysis revealed a significant association between NSCL/P and risk variants in IRF6 and the 8q24 and 10q25 loci. In contrast to previous findings, the association at the 8q24 locus was driven solely by homozygote carriers of the risk allele. This suggests that this locus might act in a recessive manner in the Mayan population. No evidence for association was found at the 17q22 locus. This may have been attributable to the limited power of the sample. CONCLUSION: These results suggest that IRF6 and the 10q25 and 8q24 loci confer a risk for the development of NSCL/P in persons of Mayan origin.

Genome-wide meta-analyses of nonsyndromic cleft lip with or without cleft palate identify six new risk loci.

We have conducted the first meta-analyses for nonsyndromic cleft lip with or without cleft palate (NSCL/P) using data from the two largest genome-wide association studies published to date. We confirmed associations with all previously identified loci and identified six additional susceptibility regions (1p36, 2p21, 3p11.1, 8q21.3, 13q31.1 and 15q22). Analysis of phenotypic variability identified the first specific genetic risk factor for NSCLP (nonsyndromic cleft lip plus palate) (rs8001641; P(NSCLP) = 6.51 × 10(-11); homozygote relative risk = 2.41, 95% confidence interval (CI) 1.84-3.16).

Genetic determination of human facial morphology: links between cleft-lips and normal variation.

Recent genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with non-syndromic cleft lip with or without cleft palate (NSCL/P), and other previous studies showed distinctly differing facial distance measurements when comparing unaffected relatives of NSCL/P patients with normal controls. Here, we test the hypothesis that genetic loci involved in NSCL/P also influence normal variation in facial morphology. We tested 11 SNPs from 10 genomic regions previously showing replicated evidence of association with NSCL/P for association with normal variation of nose width and bizygomatic distance in two cohorts from Germany (N=529) and the Netherlands (N=2497). The two most significant associations found were between nose width and SNP rs1258763 near the GREM1 gene in the German cohort (P=6 × 10(-4)), and between bizygomatic distance and SNP rs987525 at 8q24.21 near the CCDC26 gene (P=0.017) in the Dutch sample. A genetic prediction model explained 2% of phenotype variation in nose width in the German and 0.5% of bizygomatic distance variation in the Dutch cohort. Although preliminary, our data provide a first link between genetic loci involved in a pathological facial trait such as NSCL/P and variation of normal facial morphology. Moreover, we present a first approach for understanding the genetic basis of human facial appearance, a highly intriguing trait with implications on clinical practice, clinical genetics, forensic intelligence, social interactions and personal identity.