Prediction of liability to orofacial clefting using genetic and craniofacial data from parents

Cephalometric analysis of parents of patients with cleft lip and/or palate

BACKGROUND

Cleft lip and/or palate (CL ± P) or isolated cleft palate (CP) are the most common congenital malformations of the face. Although there have been advances in prenatal diagnosis and the discovery of genetic markers, there has been no breakthrough in the identification of parents at risk of giving birth to a child with a cleft.

AIMS

To determine a possible phenotypic difference in the craniofacial morphology of parents of children with CL ± P and to investigate whether cephalometric analysis can help identify parents at risk of giving birth to a child with a cleft.

METHODS

Cephalometric data of 25 sets of parents having children with CL ± P were compared with that of 25 sets of parents of children without CL ± P. The study population was indigenous to North Karnataka. In all, 10 linear, 2 angular, and 5 triangular measurements were made on lateral cephalograms and compared using an unpaired t‑test.

RESULTS

The length of the posterior cranial base (S-Ba) in mothers was smaller in the study compared to the control group. Total facial height (N-Me) both in fathers and in the group with both parents, upper facial height in the group with both parents, and lower facial height (ANS-Me) in fathers was smaller in the study than in the control group. The area of the nasopharyngeal triangle (S-PNS-Ba) in mothers and that of the anterior maxillary triangle (S-N-A) in fathers was smaller in the study group than in the control group.

CONCLUSION

Parents of children with CL ± P showed variations in craniofacial morphology. Future research correlating cephalometric findings with genetic studies may indicate whether cephalometric analysis can be an adjunct to genetic tests for risk prediction among susceptible parents.

BCL3 gene role in facial morphology

BACKGROUND

Cleft lip (CL) with or without palate (CLP) and isolated cleft palate (CP) are etiologically complex diseases with interactions among various environmental and genetic factors. The aim of the current study was to identify association with genetic markers and phenotypic craniofacial data in patients with CL/CLP/CP parents.

METHODS

Posteroanterior and lateral digital radiographs of the cranium were obtained from 74 parents of patients with CL/CLP/CP. One hundred seventy-three patients with CL/CLP/CP and 190 controls were enrolled in the study for the association test. Five genetic markers of the IRF6 gene and 14 markers of the 19q13 locus were genotyped. Linear regression analysis was performed for the relationship of cephalometric measurements with genotype data adjusted for age, gender, and cleft type. Chi-square and transmission disequilibrium tests were performed to evaluate differences in alleles of the BCL3 gene. Positive findings were replicated in an independent sample (n = 95) of patients with CL/CLP/CP parents.

RESULTS

Genetic markers of the BCL3 gene at 19q13, rs7257231, and rs1979377 in the familial association test and rs10401176 in the case-control association test, were associated with craniofacial phenotype. Carriers of BCL3 allele rs7257231T had longer posterior cranial bases than noncarriers (p(adjusted) = 0.0028), and in the familial-based association test showed the statistically strongest relationship (p(adjusted) = 0.05) to phenotype. Relation of rs7257231 to facial formation was confirmed in the replication group (p = 0.0024).

CONCLUSIONS

The results indicate that BCL3, which has functions related to cell adhesion and whose downregulation can cause disruption of ectodermal development, is likely to be important in facial formation. Birth Defects Research (Part A), 2012.

A comparative study of facial asymmetry in philippine, colombian, and ethiopian families with nonsyndromic cleft lip palate

Objective. To compare the asymmetry displayed by Philippine, Colombian, and Ethiopian unaffected parents of patients with nonsyndromic cleft palate (NSCLP) and a control population. Methods. Facial measurements were compared between unaffected parents of NSCLP patients and those in the control group for three populations from South America, Asia, and Africa by anthropometric and photographic measurements. Fluctuating and directional asymmetries, height and width proportions, were analyzed and compared. Results. Fluctuating asymmetries (ear length, middle line to Zigion perpendicular for left and right sides) and variations in the facial thirds demonstrated statistical significance in the study group of unaffected parents from Colombia and Philippines, while increased interorbital distance was evident in the unaffected Ethiopian parents of NSCLP patients. Conclusions. The facial differences in unaffected parents could indicate an underlying genetic liability. Identification of these differences has relevance in the understanding of the etiology of NSCLP.

Side of Dental Anomalies and Taurodontism as Potential Clinical Markers for Cleft Subphenotypes

Objective

The aim of this work was to investigate in more detail the dental clinical features that could serve to define subphenotypes of oral clefts.

Design

Dental records of oral cleft subjects from a group of 164 cases were examined, and 157 were included in this study. In addition, 65 families with two or more siblings born with clefts and 30 control families were evaluated to determine whether dental phenotypes were sporadic. Type of oral cleft and dental phenotypes (tooth agenesis, supernumerary teeth, taurodontism, dental transposition, and microdontia) outside the cleft area were investigated. Association of dental anomalies with preferential subtypes of cleft (subphenotype) was assessed.

Results

A total of 74 subjects presented at least one developmental dental anomaly. Tooth agenesis was the most common dental anomaly (28.6%), followed by taurodontism (15.2%). Supernumerary teeth were associated with cleft palate only ( p = .05). The absence of maxillary left lateral incisors was significantly associated with unilateral right cleft lip ( p = .02). Bilateral clefts were strongly associated with bilateral dental anomalies ( p < 0.001). In the cleft lip and palate group, tooth agenesis was associated with dental transposition ( p = .03) and with supernumerary teeth ( p = .009). Subjects with oral clefts have a higher risk of tooth agenesis (odds ratio = 3.33; 95% confidence interval, 1.18 to 10.13) and taurodontism (odds ratio = 3.95; 95% confidence interval, 2.28 to 6.82). Tooth agenesis, microdontic upper lateral incisors, and supernumerary teeth were most commonly found in unaffected siblings and parents of children born with clefts in comparison with families with no family history of clefts ( p = .01).

Conclusion

The preferential associations between specific cleft types with dental phenotypes suggest dental anomalies can be used as clinical markers to define the subphenotype isolated cleft lip and palate.

The Parental Dentocraniofacial Phenotype—An Orofacial Clefting Microform

Objective

Using the systematic review method, (1) to identify the investigations of the parental dentocraniofacial phenotype in orofacial clefting, (2) synthesize the data to derive a model of the phenotypic features that will assist in the identification of cleft morphogenes, and (3) make recommendations for the future global strategy for researching the parental craniofacial phenotype in orofacial clefting.

Search Strategy

The Cochrane, Medline (via PubMed and OVID platforms [1966 to December 2006]), Embase, CINAHL, and ASKSAM Orthodontic Reference Database (1950–1997) databases were searched using a combination of the following keywords: microform, parent, craniofacial, dental, and cleft. All published articles were reviewed. There were no exclusions of non-English reports. Of the 36 studies identified using this strategy, 26 met the inclusion criteria.

Data Abstraction/Synthesis

The statistically significant data were abstracted using a pro forma, and the methodological quality of the selected studies was evaluated using a checklist. There was considerable heterogeneity among the studies, and therefore it was not possible to synthesize the data. We were, however, able to collate the data.

Results/Conclusions

(1) The craniofacial phenotype possessed by parents of children with orofacial clefting is distinctive when compared with that of the noncleft population. (2) There is insufficient evidence to produce a model of the phenotypic features to assist in the search for orofacial clefting morphogenes. (3) The pattern of expression of the phenotypic features identified to date supports the contention that there are differences in the inheritance of cleft lip with or without cleft palate and isolated cleft palate. Progress in this field is affected by extreme heterogeneity in etiology of cleft lip with or without cleft palate, as well as heterogeneity in study design. (4) Subphenotyping using features such as microforms should be employed to reduce the heterogeneity and to improve the power of future genetic investigations and will also assist in clinical management and genetic counseling for families.

The parental craniofacial morphological features in Chinese patients with sporadic nonsyndromic cleft lip with or without palate

OBJECTIVE

To evaluate the parental craniofacial morphology in Chinese patients with sporadic nonsyndromic cleft lip with or without palate.

METHODS

A total of 98 parental pairs of nonsyndromic unilateral incomplete cleft lip children, 207 parental pairs of nonsyndromic complete cleft lip and palate children, and 206 normal persons from Sichuan University were involved in this study. A conventional cephalometric analysis was used to measure angles, linear distances, and their ratios. Two-sample Student's t tests and a multivariate discriminant analysis were applied to the data.

RESULTS

Data indicate that the unaffected parents of nonsyndromic cleft lip children had on average significantly more acute cranial base angle (Angle N-S-Ba) and larger nasal width (NC-NC') (p < .01). The healthy parents of nonsyndromic cleft lip and palate children consistently displayed a more acute cranial base angle (Angle N-S-Ba), shorter palatal length (A- PNS) and maxillary length (PNS-ANS), a more obtuse gonial angle (Angle Me-Go-Ar), and a larger y-axis length (S-Gn) and nasal width (NC-NC') (p < .01).

CONCLUSIONS

All these results indicate that the healthy parents of patients with nonsyndromic cleft lip with or without palate show distinct characteristics in craniofacial morphology. These parental craniofacial features are more obvious in patients with cleft lip with palate than those with cleft lip only. In general, the characteristics seem to be more distinct in the fathers than in the mothers of cleft patients.

Differential parental transmission of markers in RUNX2 among cleft case-parent trios from four populations

Isolated cleft lip with or without cleft palate (CL/P) is among the most common human birth defects, with a prevalence around 1 in 700 live births. The Runt-related transcription factor 2 (RUNX2) gene has been suggested as a candidate gene for CL/P based largely on mouse models; however, no human studies have focused on RUNX2 as a risk factor for CL/P. This study examines the association between markers in RUNX2 and isolated, nonsyndromic CL/P using a case-parent trio design, while considering parent-of-origin effects. Case-parent trios from four populations (77 from Maryland, 146 from Taiwan, 35 from Singapore, and 40 from Korea) were genotyped for 24 single nucleotide polymorphisms (SNPs) in the RUNX2 gene. We performed the transmission disequilibrium test on individual SNPs. Parent-of-origin effects were assessed using the transmission asymmetry test and the parent-of-origin likelihood ratio test (PO-LRT). When all trios were combined, the transmission asymmetry test revealed a block of 11 SNPs showing excess maternal transmission significant at the P<0.01 level, plus one SNP (rs1934328) showing excess paternal transmission (P=0.002). For the 11 SNPs showing excess maternal transmission, odds ratios of being transmitted to the case from the mother ranged between 3.00 and 4.00. The parent-of-origin likelihood ratio tests for equality of maternal and paternal transmission were significant for three individual SNPs (rs910586, rs2819861, and rs1934328). Thus, RUNX2 appears to influence risk of CL/P through a parent-of-origin effect with excess maternal transmission.

Abnormal maxillary trapezoid pattern in human fetal cleft lip and palate

OBJECTIVE

To elucidate abnormal growth patterns of human fetal maxillae with cleft lip and palate (CLP).

SUBJECT

A total of 71 fetal maxillae with CLP were obtained from aborted human fetuses.

METHOD

Dimensions of the maxillary trapezoid (MT), formed by the maxillary primary growth centers (MxPGC), were taken from radiographic images. The CLP dimensions were compared with maxillary trapezoid dimensions of normal fetuses from a previous study (Lee et al., 1992).

MAIN OUTCOME MEASURES

Cleft lip subjects without a cleft palate, unilateral cleft lip-alveolar cleft or cleft palate (UCL+A/UCLP), and bilateral cleft lip-alveolar cleft or cleft palate (BCL+A/BCLP) displayed abnormal MT patterns. MT abnormalities were most marked in the BCL+A/BCLP cohort.

RESULTS

The MT growth of prenatal CLP maxillae was severely arrested, resulting in abnormal MT shape on palatal radiograms. BCL+A/BCLP subjects had a more protruded nasal septum than subjects with other types of CLPs, while UCL+A/UCLP subjects showed severe deviation of the protruded nasal septum toward the noncleft side. Cleft lip-only subjects also exhibited abnormal MT growth.

CONCLUSION

MT is primarily involved in CLPs, so that the MT shape could be utilized as a sensitive indicator for the analysis of maxillary malformation in different types of CLPs.

Three-dimensional morphometric analysis of craniofacial shape in the unaffected relatives of individuals with nonsyndromic orofacial clefts: a possible marker for genetic susceptibility

Numerous studies have described altered patterns of craniofacial form in the unaffected relatives of individuals with nonsyndromic clefts. Unfortunately, results from such studies have been highly variable and have failed to provide a reliable method for differentiating "at-risk" relatives from controls. In the present study, we compared craniofacial shape between a sample of unaffected relatives (33 females; 14 males) from cleft multiplex families and an equal number of age/sex/ethnicity-matched controls. Sixteen x,y,z facial landmark coordinates derived from 3D photogrammetry were analyzed via Euclidean Distance Matrix Analysis, while 14 additional linear distances were analyzed via t tests. A subset of variables was then entered into a discriminant function analysis (DFA). Compared to controls, female unaffected relatives demonstrated increased upper facial width, midface reduction and lateral displacement of the alar cartilage. DFA correctly classified 70% of female unaffected relatives and 73% of female controls. Male unaffected relatives demonstrated increased upper facial and cranial base width, increased lower facial height and decreased upper facial height compared with controls. DFA correctly classified 86% of male unaffected relatives and 93% of male controls. In both sexes, upper facial width contributed most to group discrimination. Following DFA, unaffected relatives were assigned to risk/liability classes based on the degree of phenotypic divergence from controls. Results indicate that craniofacial shape differences characterizing unaffected relatives are partly sex-specific and are in broad agreement with previous reports. These findings further suggest that a quantitative assessment of the craniofacial phenotype may allow for the identification of susceptible individuals within nonsyndromic cleft families.

Study of the cephalometric features of parents of children with cleft lip and/or palate anomaly

The purpose of this retrospective case-control study was to compare the cephalometric features of parents of children with cleft anomalies to those of parents of normal children in the hope of finding potential markers of predisposition for this condition. There were 22 sets of parents of cleft children (study group) and 22 sets of parents of normal children (control group). A total of 88 lateral cephalograms were traced twice by two observers separately and analyzed using Student's t-test. Seven linear, two angular and five triangular cephalometric variables were measured. Mandibular body length (Go-Gn) in mothers was larger in the study than the control group, posterior cranial base (S-Ba) in fathers was shorter in the study than the control group, anterior maxillary triangle (S.N.A) in parents in the study group was larger than in the control group and posterior maxillary triangle (S.N.Pns) in study group mothers was larger than in control group mothers. In conclusion, the craniofacial morphology of the parents of children with cleft anomalies differs from that of parents of normal children and may have some predictive value.

The Pittsburgh Oral-Facial Cleft study: expanding the cleft phenotype. Background and justification

The Pittsburgh Oral-Facial Cleft study was begun in 1993 with the primary goal of identifying genes involved in nonsyndromic orofacial clefts in a variety of populations worldwide. Based on the results from a number of pilot studies and preliminary genetic analyses, a new research focus was added to the Pittsburgh Oral-Facial Cleft study in 1999: to elucidate the role that associated phenotypic features play in the familial transmission patterns of orofacial clefts in order to expand the definition of the nonsyndromic cleft phenotype. The purpose of this paper is to provide a comprehensive review of phenotypic features associated with nonsyndromic orofacial clefts. These features include fluctuating and directional asymmetry, non-right-handedness, dermatoglyphic patterns, craniofacial morphology, orbicularis oris muscle defects, dental anomalies, structural brain and vertebral anomalies, minor physical anomalies, and velopharyngeal incompetence.

Parental craniofacial morphology in cleft lip with or without cleft palate as determined by cephalometry: a meta-analysis

OBJECTIVE

To integrate findings from previous cephalometric studies comparing the craniofacial complex of unaffected parents with cleft lip with or without cleft palate (CL/P) children to controls with no history of the disease.

DESIGN

Meta-analysis of case-control cephalometric data.

INCLUSION CRITERIA

Studies were selected if the unaffected parents of children with CL/P were included and were not combined with parents of children with isolated CP; quantitative data were obtained through cephalometry; the cephalometric variables used were not unique to a study; a case-control design was used; and the means and standard deviations for all variables were reported or could be calculated for both the experimental and the control group.

OUTCOME MEASURE

Using raw data obtained from nine studies, mean weighted effect sizes with 95% confidence intervals were calculated for 28 cephalometric variables (mothers and fathers combined) or 18 variables (mothers and fathers separately). Heterogeneity statistics for the effect sizes were also calculated.

RESULTS

In general, unaffected parents of children with CL/P possessed significantly wider interorbital, nasal cavity and upper facial dimensions, narrower cranial vaults, longer cranial bases, longer and more protrusive mandibles, shorter upper faces and longer lower faces compared with controls. Increased width of the nasal cavity was the most robust finding. Significant effect size heterogeneity was observed in roughly half of the variables examined.

CONCLUSION

Unaffected parents of children with CL/P are characterized by a suite of consistent, yet subtle, craniofacial differences, which could indicate an underlying genetic liability.

Heritability of craniofacial characteristics between parents and offspring estimated from lateral cephalograms

OBJECTIVE

The purpose of the study was to estimate the heritability of different cephalometric parameters, according to lateral cephalograms, between parents and their offspring in an Icelandic population.

METHODS

The material was collected at the Faculty of Odontology, University of Iceland. The subjects were 363 children (6 years of age) and their parents. Material was also collected from the same group of children at the age of 16 years. Twenty-two reference points were identified on each cephalogram, and 33 variables were calculated, both angular and linear. Heritability was calculated at ages 6 and 16.

RESULTS

Daughters had more variables that reached the level of significance than did sons. Daughters showed similar heritability to both parents at both age levels, but more variables were highly significant ( P < or = .001) in the daughter-father groups. Sons showed stronger heritability to their mothers at both ages. The variables showing the greatest heritability were those representing the position of the lower jaw, the anterior and posterior face heights, and the cranial base dimensions. Heritability was notably low for the dental variables.

CONCLUSIONS

Genetic aberrations can be detected for complex polygenetic multifactorial traits. Cephalometric data can support predictions, and analysis of parental data could have predictive value for offspring.

Cystathionine beta-synthase c.844ins68 gene variant and non-syndromic cleft lip and palate

Non-syndromic cleft lip with or without cleft palate (CL/P) is a common birth defect with substantial clinical and social impact and whose causes include both genetic and environmental factors. Folate and homocysteine (Hcy) metabolism have been indicated to play a role in the etiology of CL/P, and polymorphisms in folate and Hcy genes may act as susceptibility factors. We investigated a common polymorphism in the cystathionine beta-synthase (CBS) gene (c.844ins68) in 134 Italian CL/P cases and their parents using the transmission disequilibrium test (TDT). Although no overall linkage disequilibrium was observed, considering the parent-of-origin transmission of the CBS 68 bp insertion a significant (P = 0.002) transmission distortion was detected. When children receive the c.844ins68 allele from the mother compared to the father, they show a 18.7-fold increase in risk for CL/P. This evidence suggests CBS as a candidate gene for CL/P and supports a role of maternal-embryo interactions in the etiology of CL/P.

Association of distinct craniofacial features in nonsyndromic cleft lip and palate family members

OBJECTIVE

To assess the relationship of distinct craniofacial features among family members with cleft lip and palate (CLP).

METHODS

Lateral cephalometric and anthropometric measurements of the members of 28 Costa Rican families with CLP were analyzed. The distinct craniofacial features in subjects with CLP were identified by comparing their craniofacial measurements with published normative values. The presence of these features was assessed in the unaffected family members. Regression coefficients were computed to evaluate the association of the distinct craniofacial measurements between parents and their offspring with and without CLP.

RESULTS

The male and female subjects with CLP were characterized by shortened head (HL), anterior cranial base (S-N), and palatal length (ANS-PNS, A-PNS) measurements as well as hyperdivergent angle of S-N plane to palatal plane (<SN-PP). All unaffected family members also had shortened S-N and ANS-PNS measurements and mothers of affected daughters also shortened HL. Mothers had a significant association in S-N, ANS-PNS, and <SN-PP measurements with their affected daughters (p <.05 for all), and fathers had a significant association in A-PNS measurement with their affected sons (p <.05). None of the associations of the distinct craniofacial measurements were significant between mothers and their unaffected daughters or between fathers and their unaffected sons.

CONCLUSION

Unaffected family members of subjects with CLP also have some distinct craniofacial features, however in lesser degree. Mothers contribute more to their affected daughters' and fathers to their affected sons' distinct craniofacial morphology.

Posteroanterior cephalometric analysis of the parental craniofacial morphology in orofacial clefting

OBJECTIVE

To evaluate the parental craniofacial morphology in orofacial clefting (OFC).

DESIGN

Case-control posteroanterior cephalometric study.

SETTING

The Department of Orthodontics, University of Dundee Dental School, Scotland, United Kingdom.

PARTICIPANTS

Ninety-two parents from a completely ascertained sample of 286 Scottish babies with nonsyndromic OFC and 43 comparison group volunteers from the University of Dundee Dental School.

MAIN OUTCOMES AND MEASURES

A conventional cephalometric analysis was used to measure linear distances and their ratios, angles, and areas. Two-sample Student's t tests and a discriminant analysis were applied to the data, and the clinically important statistically significant variables were identified using an accepted protocol.

RESULTS

Sixty-four linear distances, 10 ratios, 52 angles, and 7 areas statistically significantly differed between the parental and comparison groups (p <.01). Of these, 62 linear distances (22%), 9 ratios (45%), 41 angles (41%), and 6 areas (24%) were clinically important. Asymmetry was a feature of the results. Canonical variates analysis correctly classified 91.3% of the parental group and 90.6% of the comparison group using a series of 36 variables.

CONCLUSIONS

The parental craniofacial morphology in OFC differs significantly from the noncleft population. A larger superolateral face and smaller central midface and, in particular, a clinically significantly smaller maxillary width, in conjunction with skeletal asymmetry, characterize the parents of Scottish children with OFC. These features may be of morphogenetic importance in the etiopathogenesis of OFC in this ethnic group.

The craniofacial morphology of the parents of children with orofacial clefting: a systematic review of cephalometric studies

OBJECTIVE

To systematically review the cephalometric studies investigating the craniofacial morphology of the parents of children with orofacial clefting (OFC).

SEARCH STRATEGY

The search strategy was based on the keywords 'parent', cephalometry', and 'cleft', identifying 17 studies, of which 15 'case/control' studies met the inclusion criteria Statistically significant clinically relevant cephalometric variables from univariate statistical tests and multivariate results were collated and presented unweighted.

RESULTS/CONCLUSIONS

The parental craniofacial complex in OFC is distinctive in comparison to the non-cleft population. However, there is insufficient consistency in study designs and results to accurately characterize the parents of children with OFC. Although the craniofacial morphology of the parents of children with CL(P) differs to the parents of children with CP, there is insufficient information to accurately localize these differences.

Oral clefts and vitamin supplementation

OBJECTIVES

The evidence linking low levels of folic acid and orofacial clefting (OFC) is presently equivocal. There is stronger evidence for the role of folic acid supplementation in protection against the occurrence and recurrence of neural tube defects. The present investigation tested the hypotheses that cleft lip, cleft palate, or both are inversely associated with maternal intake of dietary and supplemental vitamins during the periconceptional period and first 4 months of pregnancy in a Brazilian population.

DESIGN

A population-based, case-control study of cleft lip with or without cleft palate (CL(P)) and isolated cleft palate (CP) in a Brazilian population. In structured interviews, case histories were taken from the mothers of a consecutive sample of 450 infants born with nonsyndromic OFC.

RESULTS

Mothers who had children with CL(P) were less likely to have been supplemented during the periconceptional period. The statistical significance of the difference in prevalence of the use of supplements between mothers of patients and of controls was greater for the CL(P) group: p < .05 for CP and p < .001 for CL(P). Multivariate analysis confirmed this finding of a protective effect for both types of orofacial cleft.

CONCLUSIONS

The use of vitamin supplements in the first 4 months of pregnancy was suggestive of a protective effect against the occurrence of CP and CL(P) in this population. The significance of an association between multivitamin supplementation and OFC and the possible role of gene/environment interaction are discussed.

Ultrasonographic detection of orbicularis oris defects in first degree relatives of isolated cleft lip patients

The phenotypic variability of non-syndromic cleft lip (CL) is broad. We demonstrate that the prevalence of orbicularis oris (OO) muscle anomalies, detectable only by ultrasound, is higher in first-degree relatives of individuals with overt CL than in the general population. These findings suggest that occult OO defects may be part of the spectrum of the CL phenotype, that offspring of individuals with such defects are at an increased risk to develop overt CL, and that ultrasound may be a useful tool in future population studies designed to identify CL susceptibility genes.