Cephalometric features in the parents of children with orofacial clefting

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.

What’s Shape Got to Do With It? Examining the Relationship Between Facial Shape and Orofacial Clefting

Nonsyndromic orofacial clefts belong to a class of congenital malformations characterized by a complex and multifactorial etiology. During early facial development, multiple factors can disrupt fusion leading to a cleft; this includes the shape of the embryonic face. The face shape hypothesis (FSH) of orofacial clefting emerged in the 1960s, influenced by morphological differences observed within affected families, comparative studies of mouse models, and advances in modeling genetic liability for complex traits in populations. For the past five decades, studies have documented changes in the shape or spatial arrangement of facial prominences in embryonic mice and altered post-natal facial shape in individuals at elevated risk for orofacial clefting due to their family history. Moreover, recent studies showing how genes that impact facial shape in humans and mice are providing clues about the genetic basis of orofacial clefting. In this review, I discuss the origins of the FSH, provide an overview of the supporting evidence, and discuss ways in which the FSH can inform our understanding of orofacial clefting.

PRICKLE1 × FOCAD Interaction Revealed by Genome-Wide vQTL Analysis of Human Facial Traits

The human face is a highly complex and variable structure resulting from the intricate coordination of numerous genetic and non-genetic factors. Hundreds of genomic loci impacting quantitative facial features have been identified. While these associations have been shown to influence morphology by altering the mean size and shape of facial measures, their effect on trait variance remains unclear. We conducted a genome-wide association analysis for the variance of 20 quantitative facial measurements in 2,447 European individuals and identified several suggestive variance quantitative trait loci (vQTLs). These vQTLs guided us to conduct an efficient search for gene-by-gene (G × G) interactions, which uncovered an interaction between PRICKLE1 and FOCAD affecting cranial base width. We replicated this G × G interaction signal at the locus level in an additional 5,128 Korean individuals. We used the hypomorphic Prickle1 Beetlejuice (Prickle1 Bj ) mouse line to directly test the function of Prickle1 on the cranial base and observed wider cranial bases in Prickle1 Bj/Bj . Importantly, we observed that the Prickle1 and Focadhesin proteins co-localize in murine cranial base chondrocytes, and this co-localization is abnormal in the Prickle1 Bj/Bj mutants. Taken together, our findings uncovered a novel G × G interaction effect in humans with strong support from both epidemiological and molecular studies. These results highlight the potential of studying measures of phenotypic variability in gene mapping studies of facial morphology.

Soft tissue nasal asymmetry as an indicator of orofacial cleft predisposition

The biological relatives of offspring with nonsyndromic orofacial clefts have been shown to exhibit distinctive facial features, including excess asymmetry, which are hypothesized to indicate the presence of genetic risk factors. The significance of excess soft tissue nasal asymmetry in at-risk relatives is unclear and was examined in the present study. Our sample included 164 unaffected parents from families with a history of orofacial clefting and 243 adult controls. Geometric morphometric methods were used to analyze the coordinates of 15 nasal landmarks collected from three-dimensional facial surface images. Following generalized Procrustes analysis, Procrustes ANOVA and MANOVA tests were applied to determine the type and magnitude of nasal asymmetry present in each group. Group differences in mean nasal asymmetry were also assessed via permutation testing. We found that nasal asymmetry in both parents and controls was directional in nature, although the magnitude of the asymmetry was greater in parents. This was confirmed with permutation testing, where the mean nasal asymmetry was significantly different (p < .0001) between parents and controls. The asymmetry was greatest for midline structures and the nostrils. When subsets of parents were subsequently analyzed and compared (parents with bilateral vs. unilateral offspring; parents with left vs. right unilateral offspring), each group showed a similar pattern of asymmetry and could not be distinguished statistically. Thus, the side of the unilateral cleft (right vs. left) in offspring was not associated with the direction of the nasal asymmetry in parents.

Testing the face shape hypothesis in twins discordant for nonsyndromic orofacial clefting

Nonsyndromic orofacial clefts (OFCs) are complex traits characterized by multifactorial inheritance and wide phenotypic variability. Numerous studies have shown subtle differences in the faces of unaffected relatives from cleft families compared to controls, the implication being that such outward differences are an incomplete expression reflecting an underlying genetic predisposition. Twins discordant for OFCs provide a unique opportunity to further test this idea, as the unaffected co-twin shares on average 50% (for dizygotic twins) and 100% (for monozygotic twins) of the genetic risk factors as the affected twin. We used 3D surface imaging and spatially-dense morphometry to compare facial shape in a sample of 44 unaffected co-twins and age- and sex-matched unaffected controls (n = 241). Unaffected co-twins showed statistically significant differences in the midface, lateral upper face, and forehead regions, compared to controls. Furthermore, co-twins were characterized by a distinct pattern of midfacial retrusion, broader upper faces, and greater protrusion of the mandible and brow ridges. This same general facial pattern was shown in both unaffected monozygotic and dizygotic co-twin subsets. These results provide additional support that altered facial shape is a phenotypic marker for OFC susceptibility.

Communication and cognition profiles in parents of children with nonsyndromic cleft lip and/or palate

The main aim of the study was to ascertain whether parents of children with nonsyndromic cleft lip and/or palate (P-CLP) perform differently than parents of children without CLP (P-control) on a nonword repetition (NWR) test. Given that children with CLP frequently demonstrate communication and cognitive difficulties, a link between NWR performance and group would lend support to a familial risk factor in nonsyndromic CLP. The NWR test, a well-documented assessment to identify language and cognitive impairment, was used, together with a parent questionnaire to gather demographic data and family history information on medical, communication, and/or cognitive difficulties for 260 parents. Group differences on NWR performance and family history of communication and cognition difficulties were not demonstrated. Also, no significant difference on NWR score was seen in the P-CLP group based on child's CLP type. Correlation analysis showed that having more years of schooling, English as the dominant language, living in private housing, and being in skilled occupations were positively correlated to NWR score. Controlling for these known background variables did not alter NWR performance between P-CLP and P-control, however, only years of schooling significantly and consistently predicted NWR performance. Having significantly fewer years of schooling in the P-CLP group could be suggestive of an increased risk of communication and cognitive difficulties these parents face, and the potential difficulties their children with CLP may encounter. These results may inform early and rigorous intervention strategies for children with CLP.

Evaluation of Parental Nasomaxillary Asymmetry as a Risk Factor for Development of Palatal Clefts in their Offsprings

Background and Objectives : It has been suggested previously that increased width of midfacial structure is associated with the development of palatal clefting. One of the most important heritable characteristics predisposing towards the development of orofacial clefting in an embryo is craniofacial morphology. The aim of the study was to compare nasomaxillary width of parents of children with unilateral complete cleft lip alveolus and palate with parents of noncleft children. Methods : 25 biologic parent sets of children with unilateral complete cleft lip alveolus and palate and 25 biologic parents of noncleft children were included in this study for PA cephalometric analysis. Results : There was no statistically significant difference between study and control groups. An association was found between the side of the cleft in the affected children and the parents in the same side with narrower nasomaxillary width. Interpretation and conclusion : The result of this study was in contrast with other previous studies. We observed a narrower nasomaxillary width, which suggested that this feature may be of morphogenetic importance in the etiopathogenesis of orofacial clefting in this geographic and ethnic group.

Asymmetry of the craniofacial skeleton in the parents of children with a cleft lip, with or without a cleft palate, or an isolated cleft palate

The objective of this study was to evaluate asymmetry of the parental craniofacial skeleton of subjects with a cleft lip, with or without cleft palate [CL(P)], and isolated cleft palate (CP). The postero-anterior (PA) cephalograms of 52 parents of children with CL(P) and 40 parents of children with CP from a sample of 196 children with non-syndromic clefts in the west of Scotland were analysed. A conventional cephalometric asymmetry analysis was used to evaluate size-related right:left asymmetry comprising eight linear distances, nine angular, and three facial area measurements. Right:left ratios of the mean values identified the direction of the asymmetry and two-sample t-tests determined statistical significance. A shape-related asymmetry analysis was also undertaken. The configurations of landmarks were optimally superimposed and scaled using Procrustes algorithms. Euclidean distance matrix analysis (EDMA) was then compared and the shape of the left and the right landmark configurations were statistically tested using a non-parametric bootstrap technique. For the parents of CL(P) children, size-related asymmetry was identified and the area of the craniofacial polygon was statistically significantly larger on the right than on the left side. EDMA detected the presence of shape-related asymmetry (T statistic = 1.304; P = 0.003). For the parents of CP children, although size-related asymmetry was identified, EDMA did not identify shape-related asymmetry (T statistic = 1.281; P = 0.065). Size and shape directional asymmetries are characteristic features of the parental craniofacial skeleton in CL(P). Although directional size asymmetry is present in the parental craniofacial skeleton in CP, shape asymmetry is not a characteristic feature.

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.

Face shape of unaffected parents with cleft affected offspring: combining three-dimensional surface imaging and geometric morphometrics

OBJECTIVE

Various lines of evidence suggest that face shape may be a predisposing factor for non-syndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non-cleft) parents of individuals with CL / P and unrelated controls.

METHODS

Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls.

RESULTS

Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL/P. Shape changes associated with CL/P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height, and excess interorbital width. Additionally, a sex-specific pattern of parent-control difference was evident in the transverse dimensions of the nasolabial complex.

CONCLUSIONS

The faces of unaffected parents from multiplex cleft families displayed meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL/P.

Cleft lip and palate

Clefts of the lip and palate are generally divided into two groups, isolated cleft palate and cleft lip with or without cleft palate, representing a heterogeneous group of disorders affecting the lips and oral cavity. These defects arise in about 1.7 per 1000 liveborn babies, with ethnic and geographic variation. Effects on speech, hearing, appearance, and psychology can lead to longlasting adverse outcomes for health and social integration. Typically, children with these disorders need multidisciplinary care from birth to adulthood and have higher morbidity and mortality throughout life than do unaffected individuals. This Seminar describes embryological developmental processes, epidemiology, known environmental and genetic risk factors, and their interaction. Although access to care has increased in recent years, especially in developing countries, quality of care still varies substantially. Prevention is the ultimate objective for clefts of the lip and palate, and a prerequisite of this aim is to elucidate causes of the disorders. Technological advances and international collaborations have yielded some successes.

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.

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.

Predisposing factors to formation of cleft lip and palate: inherited craniofacial skeletal morphology

OBJECTIVE

To identify inherited craniofacial morphologic features in individuals at high risk for cleft of the lip, cleft palate, or both.

SUBJECTS

Twins without cleft from 33 pairs of monozygotic twins discordant for cleft lip, cleft palate, or both were studied. There were 17 males and 16 females of Caucasian origin, ranging from 3 to 18 years (15 with cleft lip and palate [CLP], 10 with cleft lip [CL], and 8 with cleft palate [CP]), collected from five craniofacial centers (United States and Canada).

DESIGN

The twin without cleft (noncleft) from each set was compared with an age- and sex-matched control individual from the Burlington Growth Centre, Toronto, Ontario. Posteroanterior and lateral cephalograms were traced and digitized using a computer custom analysis. Descriptive statistics, Student's t tests, and analysis of variance were used to test 40 variables in a pilot study comparing the noncleft twin groups with the controls. Preliminary analysis permitted pooling of the CLP and CL groups (n = 25). To minimize false-positive significance, only 14 variables (from the maxillofacial area) were tested.

RESULTS

Using the raw probabilities, eight variables showed significant differences between the pooled noncleft CLP and CL (CL[P]) twin group and the controls. However, when the level of significance was adjusted, only four (nasal width [p < .01], cranial base length [p < .05], cranial base width/length ratio [p < .001], and maxillary width/length ratio [p < .05]) were significantly different. No significant differences were confirmed between the noncleft CP twin group and the controls.

CONCLUSIONS

The noncleft member of a discordant monozygotic pair has a number of facial characteristics that differ from the general population. These may predispose to the formation of a cleft lip or palate and may result from a deficiency or distortion of the mesenchyme that forms the craniofacial structures.

Finite element growth analysis for the craniofacial skeleton in patients with cleft lip and palate

The purpose of this study was to clarify the differences in the nature of craniofacial growth between subjects with normal occlusion and patients with unilateral cleft lip and palate (CLP) in terms of the size, shape and principal growth direction of craniofacial skeleton using finite element method (FEM). Lateral cephalograms were taken of 40 subjects as normal group and 178 patients as CLP group. These subjects were divided into seven developmental ages of 4-, 6-, 8-, 10-, 12-, 14- and 18-year-old. For the finite element analysis, the craniofacial complex was discretized into seven structures or elements with three nodal points in each after tracing each lateral cephalogram on acetate paper. For each stage, the growth parameters in CLP group were compared to those in normal group. The growth of upper facial skeleton and maxillary complex was more remarkably inhibited in CLP than in normal group. Especially, the growth inhibition of posterior maxillary complex in a vertical direction was remarkable in CLP group at any ages. Difference in the size and shape of entire mandibular skeleton between CLP and normal groups was not apparent. It is suggested that grow timing and peak velocity, an essential and key determinant to the success in orthodontic treatment, have been clarified in this study more clearly than in previous studies. It is hopefully anticipated to explore some key determinants to predict individual growth of the craniofacial skeleton near future.

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.

Asymmetry of the parental craniofacial skeleton in orofacial clefting

OBJECTIVE

To evaluate size-related and shape-related craniofacial skeletal asymmetries in the parents of children with orofacial clefting (OFC).

DESIGN

Retrospective PA cephalometric study.

SETTING

Glasgow/Dundee, Scotland.

SUBJECTS

Ninety-two parental volunteers from a completely ascertained sample of 286 children born with OFC between 1980-1984 in the West of Scotland.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

A conventional cephalometric asymmetry analysis (CCAA) evaluated size-related right:left asymmetry comprising eight linear distance, nine angular, and three mid-facial area measurements. The right and left landmark configurations were uniformly scaled using Procrustes superimposition and Euclidean Distance Matrix Analysis (EDMA) evaluated shape-related right-left asymmetry.

RESULTS

The three linear distances, nine angles and two areas differed between the right and left sides of the craniofacial complex (P <0.05) indicate size asymmetry characterized by a wider left side of the face and a shorter vertical dimension on the right side (directional asymmetry). EDMA detected shape asymmetry [T statistic = 2.671 (P = 0.10)]. Forty per cent of the EDMA ratios were clinically importantly larger or smaller on the left and right sides respectively, involving landmarks anatomically and morphogenetically important in OFC.

CONCLUSION

Size and shape directional asymmetries characterize the parental craniofacial skeleton in OFC. This heritable directional craniofacial skeletal asymmetry could be of relevance in the left-sided predilection of OFC.

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.

Cranial base growth and morphology in second-trimester normal human fetuses and fetuses with cleft lip

OBJECTIVE

The present radiographic study describes the size and shape of the cranial base from the sagittal aspect for a sample of 77 second-trimester "normal" control fetuses (n = 61) and fetuses (n = 16) exhibiting isolated, unilateral clefts of the lip (CL), ranging in fertilization age from 10 to 22 weeks.

METHODS

Fetuses were placed in a cephalostat, and standardized, lateral head radiographs were taken. The radiographs were traced, and 15 cephalometric landmarks were identified and digitized for analysis. Growth curves for cranial base lengths, angles, and areas were compared between control and CL groups. Also, cranial base triangles were constructed and shape comparisons were made using tensor biometric analysis.

RESULTS

No significant differences (p >.05) in regression line slopes were noted for any comparisons between the control and CL samples. Tensor biometric analysis also revealed no significant differences in the shapes of various cranial base triangles between the control and CL samples.

CONCLUSION

This report presents second-trimester baseline growth curves for various cranial base components in CL human fetal specimens, and these data suggest that CL fetuses may also be used as an appropriate control sample for prenatal growth comparison studies of cleft lip and palate and cleft palate.