Search

Nonsyndromic orofacial clefts (OFCs) are among the most common craniofacial birth defects worldwide, and known to exhibit phenotypic and genetic heterogeneity. Cleft lip plus cleft palate (CLP) and cleft lip only (CL) are commonly combined together as one phenotype (CL/P), separately from cleft palate alone. In comparison, our study analyzes CL and CLP separately. A sample of 2218 CL and CLP cases, 4537 unaffected relatives of cases, and 2673 pure controls with no family history of OFC were selected from the Pittsburgh Orofacial Cleft (Pitt-OFC) multiethnic study.genome-wide association studies were run for seven specific phenotypes created based on the cleft type(s) observed within these families, as well as the combined CL/P phenotype. Five novel genome-wide significant associations, 3q29 (rs62284390), 5p13.2 (rs609659), 7q22.1 (rs6465810), 19p13.3 (rs628271), and 20q13.33 (rs2427238), and nine associations (p ≤ 1.0E-05) within previously confirmed OFC loci-PAX7, IRF6, FAM49A, DCAF4L2, 8q24.21, ARID3B, NTN1, TANC2 and the WNT9B:WNT3 gene cluster-were observed. We also found that single nucleotide polymorphisms within a subset of the associated loci, both previously known and novel, differ substantially in terms of their effects across cleft- or family-specific phenotypes, indicating not only etiologic differences between CL and CLP, but also genetic heterogeneity within each of the two OFC subtypes., (© 2022 Wiley Periodicals LLC.)

Background: Dental caries is one of the most common chronic diseases and is influenced by a complex interplay of genetic and environmental factors. Most previous genetic studies of caries have focused on identifying genes that contribute to dental caries in specific ethnic groups, usually of European descent., Methods: The aim of this study is to conduct a genome-wide association study (GWAS) to identify associations affecting susceptibility to caries in a large multiethnic population from Argentina, the Philippines, Guatemala, Hungary, and the USA, originally recruited for studies of orofacial clefts (POFC, N = 3686). Ages of the participants ranged from 2 to 12 years for analysis of the primary dentition, and 18-60 years for analysis of the permanent dentition. For each participant, dental caries was assessed by counts of decayed and filled teeth (dft/DFT) and genetic variants (single nucleotide polymorphisms, SNPs) were genotyped or imputed across the entire genome. Caries was analyzed separately for the primary and permanent dentitions, with age, gender, and presence/absence of any type of OFC treated as covariates. Efficient Mixed-Model Association eXpedited (EMMAX) was used to test genetic association, while simultaneously accounting for relatedness and stratification., Results: We identified several suggestive loci (5 × 10 -8  < P < 5 × 10 -6 ) within or near genes with plausible biological roles for dental caries, including a cluster of taste receptor genes (TAS2R38, TAS2R3, TAS2R4, TASR25) on chromosome 7 for the permanent dentition analysis, and DLX3 and DLX4 on chromosome 17 for the primary dentition analysis. Genome-wide significant results were seen with SNPs in the primary dentition only; however, none of the identified genes near these variants have known roles in cariogenesis., Conclusion: The results of this study warrant further investigation and may lead to a better understanding of cariogenesis in diverse populations, and help to improve dental caries prediction, prevention, and/or treatment in future., (© 2021. The Author(s).)

Dermatoglyphic patterns on the fingers often differ in syndromes and other conditions with a developmental component, compared to the general population. Previous literature on the relationship between orofacial clefts-the most common craniofacial birth defect in humans-and dermatoglyphics is inconsistent, with some studies reporting altered pattern frequencies and/or increased asymmetry and others failing to find differences. To investigate dermatoglyphics in orofacial clefting, we obtained dermatoglyphic patterns in a large multiethnic cohort of orofacial cleft cases (N = 367), their unaffected family members (N = 836), and controls (N = 299). We categorized fingerprint pattern types from males and females who participated at five sites of the Pittsburgh Orofacial Cleft study (Hungary, United States of America (Pennsylvania, Texas), Spain, and Argentina). We also calculated a pattern dissimilarity score for each individual as a measure of left-right asymmetry. We tested for group differences in the number of arches, ulnar and radial loops, and whorls on each individual's hands, and in the pattern dissimilarity scores using ANOVA. After taking sex and site differences into account, we did not find any significant pattern count differences between cleft and non-cleft individuals. Notably, we did observe increased pattern dissimilarity in individuals with clefts, compared to both their unaffected relatives and controls. Increased dermatoglyphic pattern dissimilarity in individuals with nonsyndromic orofacial clefts may reflect a generalized developmental instability., Competing Interests: The authors have declared that no competing interests exist.

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is the most common craniofacial birth defect in humans and is notable for its apparent sexual dimorphism where approximately twice as many males are affected as females. The sources of this disparity are largely unknown, but interactions between genetic and sex effects are likely contributors. We examined gene-by-sex (G × S) interactions in a worldwide sample of 2,142 NSCL/P cases and 1,700 controls recruited from 13 countries. First, we performed genome-wide joint tests of the genetic (G) and G × S effects genome-wide using logistic regression assuming an additive genetic model and adjusting for 18 principal components of ancestry. We further interrogated loci with suggestive results from the joint test ( p < 1.00 × 10 -5 ) by examining the G × S effects from the same model. Out of the 133 loci with suggestive results ( p < 1.00 × 10 -5 ) for the joint test, we observed one genome-wide significant G × S effect in the 10q21 locus (rs72804706; p = 6.69 × 10 -9 ; OR = 2.62 CI [1.89, 3.62]) and 16 suggestive G × S effects. At the intergenic 10q21 locus, the risk of NSCL/P is estimated to increase with additional copies of the minor allele for females, but the opposite effect for males. Our observation that the impact of genetic variants on NSCL/P risk differs for males and females may further our understanding of the genetic architecture of NSCL/P and the sex differences underlying clefts and other birth defects., (© 2018 Wiley Periodicals, Inc.)

The 19q13 locus has been linked to cleft lip and palate by our group and independently by others. Here we fine mapped the region in an attempt to identify an etiological variant that can explain cleft lip and palate occurrence. A total of 2739 individuals born with cleft lip and palate, related to individuals born with cleft lip and palate, and unrelated were studied. We used linkage and association approaches to fine map the interval between D19S714 and D19S433 and genotypes were defined by the use of TaqMan chemistry. We confirmed our previous findings that markers in PVR/CD155 are associated with cleft lip and palate. We studied the mutation Ala67Thr further and calculated its penetrance. We also attempted to detect PVR/CD155 expression in human whole saliva. Our results showed that markers in PVR/CD155 are associated with cleft lip and palate and the penetrance of the Ala67Thr is very low (between 1% and 5%). We could not detect PVR/CD155 expression in adult human whole saliva and PVR/CD155 possibly interacts with maternal infection to predispose children to cleft lip only.

Increased susceptibility to cleft lip, with or without cleft palate (CL±P) has been observed in South America, as related to Amerindian ancestry, using epidemiological data, uniparental markers, and blood groups. In this study, it was evaluated whether this increased risk remains when Amerindian ancestry is estimated using autosomal markers and considered in the predictive model. Ancestry was estimated through genotyping 62 insertion and deletion (INDEL) markers in sample sets of patients with CL±P, patients with cleft palate (CP), and controls, from Patagonia in southern Argentina and Belém in northern Brazil. The Amerindian ancestry in patients from Patagonia with CL±P was greater than in controls although it did not reach statistical significance. The European ancestry in patients with CL±P from Belém and in patients with CP from Belém and Patagonia was higher than in controls and statistically significant for patients with CP who were from Belém. This high contribution of European genetic ancestry among patients with CP who were from Belém has not been previously observed in American populations. Our results do not corroborate the currently accepted risks for CL±P and CP estimated by epidemiological studies in the North American populations and probably reflect the higher admixture found in South American ethnic groups when compared with the same ethnic groups from the North American populations., (© 2016 Eur J Oral Sci.)

Orofacial clefts (OFCs), which include non-syndromic cleft lip with or without cleft palate (CL/P), are among the most common birth defects in humans, affecting approximately 1 in 700 newborns. CL/P is phenotypically heterogeneous and has a complex etiology caused by genetic and environmental factors. Previous genome-wide association studies (GWASs) have identified at least 15 risk loci for CL/P. As these loci do not account for all of the genetic variance of CL/P, we hypothesized the existence of additional risk loci. We conducted a multiethnic GWAS in 6480 participants (823 unrelated cases, 1700 unrelated controls and 1319 case-parent trios) with European, Asian, African and Central and South American ancestry. Our GWAS revealed novel associations on 2p24 near FAM49A, a gene of unknown function (P = 4.22 × 10 -8 ), and 19q13 near RHPN2, a gene involved in organizing the actin cytoskeleton (P = 4.17 × 10 -8 ). Other regions reaching genome-wide significance were 1p36 (PAX7), 1p22 (ARHGAP29), 1q32 (IRF6), 8q24 and 17p13 (NTN1), all reported in previous GWASs. Stratification by ancestry group revealed a novel association with a region on 17q23 (P = 2.92 × 10 -8 ) among individuals with European ancestry. This region included several promising candidates including TANC2, an oncogene required for development, and DCAF7, a scaffolding protein required for craniofacial development. In the Central and South American ancestry group, significant associations with loci previously identified in Asian or European ancestry groups reflected their admixed ancestry. In summary, we have identified novel CL/P risk loci and suggest new genes involved in craniofacial development, confirming the highly heterogeneous etiology of OFCs., (© The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background : There is disagreement about the association between cleft lip with or without cleft palate and multigravidity, which could be explained by differences of adjusting for maternal age, Amerindian ancestry, and socioeconomic status. Objective : The aim was to evaluate gravidity 4+ (four or more gestations) as a risk factor for cleft lip with or without cleft palate in South America. Design : We used a matched (1:1) case-control study with structural equation modeling for related causes. Data were obtained from 1,371,575 consecutive newborn infants weighing ≥500 g who were born in the hospitals of the Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC) network between 1982 and 1999. There were a total of 1,271 cases with cleft lip with or without cleft palate (excluding midline and atypical cleft lip with or without cleft palate). A total of 1,227 case-control pairs were obtained, matched by maternal age, newborn gender, and year and place of birth. Potential confounders and intermediary variables were analyzed with structural equation modeling. Results : The crude risk of gravidity 4+ was 1.41 and the 95% confidence interval was 1.14 to 1.61. When applying structural equation modeling, the effect of multigravidity on the risk of cleft lip with or without cleft palate was 1.22 and the 95% confidence interval was 0.91 to 1.39. Conclusions : Multigravid mothers (more than four gestations) showed no greater risk of bearing children who had cleft lip with or without cleft palate than mothers with two or three births. Therefore, the often observed and reported association between multigravidity and oral clefts likely reflects the effect of other risk factors related to low socioeconomic status in South American populations.

We have previously shown the association of AXIN2 with oral clefts in a US population. Here, we expanded our study to explore the association of 11 AXIN2 markers in 682 cleft families from multiple populations. Alleles for each AXIN2 marker were tested for transmission distortion with clefts by means of the Family-based Association Test. We observed an association with SNP rs7224837 and all clefts in the combined populations (p = 0.001), and with SNP rs3923086 and cleft lip and palate in Asian populations (p = 0.004). We confirmed our association findings in an additional 528 cleft families from the United States (p < 0.009). We tested for gene-gene interaction between AXIN2 and additional cleft susceptibility loci. We assessed and detected Axin2 mRNA and protein expression during murine palatogenesis. In addition, we also observed co-localization of Axin2 with Irf6 proteins, particularly in the epithelium. Our results continue to support a role for AXIN2 in the etiology of human clefting. Additional studies should be performed to improve our understanding of the biological mechanisms linking AXIN2 to oral clefts.

Nonsyndromic cleft lip with or without cleft palate (CL/P) is a common birth defect due to both genetic and environmental factors. Whorl lip print patterns are circular grooves on the central upper lip and/or the left and right lower lip. To determine if whorls are more common in families with CL/P than in controls, the Pittsburgh Orofacial Cleft Study collected lip prints from over 450 subjects, that is, individuals with CL/P, their relatives, and unrelated controls-from the U.S., Argentina, and Hungary. Using a narrow definition of lower-lip whorl, the frequency of whorls in the U.S. sample was significantly elevated in cleft individuals and their family members, compared to unrelated controls (14.8% and 13.2% vs. 2.3%; P = 0.003 and 0.001, respectively). Whorls were more frequent in CL/P families from Argentina than in CL/P families from the U.S. or Hungary. If these results are confirmed, whorl lip print patterns could be part of an expanded phenotypic spectrum of nonsyndromic CL/P. As such, they may eventually be useful in a clinical setting, allowing recurrence risk calculations to incorporate individual phenotypic information in addition to family history data.

The aim of this work was to search for unequal birth prevalence rates (BPRs) of cleft lip +/- cleft palate (CL/P), and cleft palate only (CPO), among different geographic areas in South America, and to analyze phenotypic characteristics and associated risk factors in each identified cluster. Included were 5,128 CL/P cases, 1,745 CPO cases, and 3,712 controls (like-sexed, non-malformed liveborn infant, born immediately after a malformed one, in the same hospital), over 4,199,630 consecutive births. They were ascertained between 1967 and 2004, in 190 maternity hospitals of the ECLAMC (Estudio Colaborativo Latinoamericano de Malformaciones Congénitas) network, in 102 cities of all 10 South American countries. Non-predefined geographical areas with significantly unusual cleft BPRs were identified with Kulldorf and Nagarwalla's spatial scan statistic, employing number of cases and births, and exact location of each hospital. Expected values were cleft BPRs registered for the entire ECLAMC hospital network. Syndromic and non-syndromic clefts were considered for cluster analysis, and phenotypic characterization, while only non-syndromic for risk factor analysis. Seven clusters for CL/P, and four for CPO, with unusual BPRs were identified. CL/P cases in high BPR areas were more severe than elsewhere in the sample, similar to a previous ECLAMC report on microtia. For CL/P, high BPR clusters were associated with high altitude above sea level, Amerindian ancestry, and low socioeconomic strata; low BPR clusters showed association with African Black ancestry. Advanced maternal age, a recognized risk factor for CPO, was also associated with the only identified geographic cluster for CPO., ((c) 2007 Wiley-Liss, Inc.)