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

Craniofacial morphological variability in orthodontic patients with non-syndromic orofacial clefts: an approach using geometric morphometrics

OBJECTIVES

Orofacial clefts are complex congenital anomalies that call for comprehensive treatment based on a thorough assessment of the anatomy. This study aims to examine the effect of cleft type on craniofacial morphology using geometric morphometrics.

MATERIALS AND METHODS

We evaluated lateral cephalograms of 75 patients with bilateral cleft lip and palate, 63 patients with unilateral cleft lip and palate, and 76 patients with isolated cleft palate. Generalized Procrustes analysis was performed on 16 hard tissue landmark coordinates. Shape variability was studied with principal component analysis. In a risk model approach, the first nine principal components (PC) were used to examine the effect of cleft type.

RESULTS

We found statistically significant differences in the mean shape between cleft types. The difference is greatest between bilateral cleft lip and palate and isolated cleft palate (distance of means 0.026, P = 0.0011). Differences between cleft types are most pronounced for PC4 and PC5 (P = 0.0001), which together account for 10% of the total shape variation. PC4 and PC5 show shape differences in the ratio of the upper to the lower face, the posterior mandibular height, and the mandibular angle.

CONCLUSIONS

Cleft type has a statistically significant but weak effect on craniofacial morphological variability in patients with non-syndromic orofacial clefts, mainly in the vertical dimension.

CLINICAL RELEVANCE

Understanding the effects of clefts on craniofacial morphology is essential to providing patients with treatment tailored to their specific needs. This study contributes to the literature particularly due to our risk model approach in lieu of a prediction model.

The heterogeneous genetic architectures of orofacial clefts

Orofacial clefts (OFCs) are common, affecting 1:1000 live births. OFCs occur across a phenotypic spectrum - including cleft lip (CL), cleft lip and palate (CLP), or cleft palate (CP) - and can be further subdivided based on laterality, severity, or specific structures affected. Herein we review what is known about the genetic architecture underlying each of these subtypes, considering both shared and subtype-specific risks. While there are more known genetic similarities between CL and CLP than CP, recent research supports both shared and subtype-specific genetic risk factors within and between phenotypic classifications of OFCs. Larger sample sizes and deeper phenotyping data will be of increasing importance for the discovery of novel genetic risk factors for OFCs and various subtypes going forward.

Rare variants found in multiplex families with orofacial clefts: Does expanding the phenotype make a difference?

Exome sequencing (ES) is now a relatively straightforward process to identify causal variants in Mendelian disorders. However, the same is not true for ES in families where the inheritance patterns are less clear, and a complex etiology is suspected. Orofacial clefts (OFCs) are highly heritable birth defects with both Mendelian and complex etiologies. The phenotypic spectrum of OFCs may include overt clefts and several subclinical phenotypes, such as discontinuities in the orbicularis oris muscle (OOM) in the upper lip, velopharyngeal insufficiency (VPI), microform clefts or bifid uvulas. We hypothesize that expanding the OFC phenotype to include these phenotypes can clarify inheritance patterns in multiplex families, making them appear more Mendelian. We performed exome sequencing to find rare, likely causal genetic variants in 31 multiplex OFC families, which included families with multiple individuals with OFCs and individuals with subclinical phenotypes. We identified likely causal variants in COL11A2, IRF6, SHROOM3, SMC3, TBX3, and TP63 in six families. Although we did not find clear evidence supporting the subclinical phenotype hypothesis, our findings support a role for rare variants in the etiology of OFCs.

A Retrospective and Prospective Cohort Study Comparing Pediatric Patients With Cleft Lip and Palate From the United States and Guatemala

Orofacial clefts (OFC) remain among the most prevalent congenital abnormalities worldwide. In the United States in 2010 to 2014, 16.2 of 10,000 live births are born with OFC compared with 23.6 of 10,000 in Alta Verapaz, Guatemala in 2012. Demographics and cleft severity scores were retrospectively gathered from 514 patients with isolated OFC at the Children's Hospital of Philadelphia scheduled for surgery from 2012 to 2019 and from 115 patients seen during surgical mission trips to Guatemala City from 2017 to 2020. Risk factors were also gathered prospectively from Guatemalan families. The Guatemalan cohort had a significantly lower prevalence of cleft palate only compared with the US cohort, which may be a result of greater cleft severity in the population or poor screening and subsequent increased mortality of untreated cleft palate. Of those with lip involvement, Guatemalan patients were significantly more likely to have complete cleft lip, associated cleft palate, and right-sided and bilateral clefts, demonstrating an increased severity of Guatemalan cleft phenotype. Primary palate and lip repair for the Guatemalan cohort occurred at a significantly older age than that of the US cohort, placing Guatemalan patients at increased risk for long-term complications such as communication difficulties. Potential OFC risk factors identified in the Guatemalan cohort included maternal cooking-fire and agricultural chemical exposure, poor prenatal vitamin intake, poverty, and risk factors related to primarily corn-based diets. OFC patients who primarily rely on surgical missions for cleft care would likely benefit from more comprehensive screening and investigation into risk factors for more severe OFC phenotypes.

Disruption of fos causes craniofacial anomalies in developing zebrafish

Craniofacial development is a complex and tightly regulated process and disruptions can lead to structural birth defects, the most common being nonsyndromic cleft lip and palate (NSCLP). Previously, we identified FOS as a candidate regulator of NSCLP through family-based association studies, yet its specific contributions to oral and palatal formation are poorly understood. This study investigated the role of fos during zebrafish craniofacial development through genetic disruption and knockdown approaches. Fos was expressed in the periderm, olfactory epithelium and other cell populations in the head. Genetic perturbation of fos produced an abnormal craniofacial phenotype with a hypoplastic oral cavity that showed significant changes in midface dimensions by quantitative facial morphometric analysis. Loss and knockdown of fos caused increased cell apoptosis in the head, followed by a significant reduction in cranial neural crest cells (CNCCs) populating the upper and lower jaws. These changes resulted in abnormalities of cartilage, bone and pharyngeal teeth formation. Periderm cells surrounding the oral cavity showed altered morphology and a subset of cells in the upper and lower lip showed disrupted Wnt/β-catenin activation, consistent with modified inductive interactions between mesenchymal and epithelial cells. Taken together, these findings demonstrate that perturbation of fos has detrimental effects on oral epithelial and CNCC-derived tissues suggesting that it plays a critical role in zebrafish craniofacial development and a potential role in NSCLP.

IRF6 and FGF1 polymorphisms in non-syndromic cleft lip with or without cleft palate in the Polish population

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is the most common developmental defect that significantly affects the morphology and function of the stomatognathic system in children. The etiology of these birth defects is multifactorial, and single nucleotide polymorphisms (SNPs) in IRF6 and FGF1 have been associated with NSCL/P. This study aimed to evaluate whether SNPs in IRF6, namely rs2013162, rs642961, rs2235373, and rs34010 in FGF1, are associated with NSCL/P occurrence in the Polish population. The study included 627 participants: 209 children with NSCL/P and 418 healthy controls. DNA was isolated from saliva in the study group and from umbilical cord blood in controls. Genotyping of polymorphisms was performed using quantitative PCR. There was no statistically significant association of IRF6 gene variants with NSCL/P occurrence, although for rs2013162, AA genotype, odds ratio (OR) = 1.16 and for AC genotype, OR = 0.83; for rs642961, AA genotype, OR = 0.84 and for AG genotype, OR = 1.41; and for rs2235373, AA genotype, OR = 0.79 and for AG, OR = 0.85. In the instance of rs34010 polymorphism in FGF1, the presence of the AA genotype was statistically significant in reducing the risk of NSCL/P (OR = 0.31, p = 0.001). Genetic variation in FGF1 is an important risk marker of NSCL/P in the Polish population, which cannot be stated for the polymorphisms in the IRF6 gene.

Rare variants found in multiplex families with orofacial clefts: Does expanding the phenotype make a difference?

Whole-exome sequencing (WES) is now a relatively straightforward process to identify causal variants in Mendelian disorders. However, the same is not true for WES in families where the inheritance patterns are less clear, and a complex etiology is suspected. Orofacial clefts (OFCs) are highly heritable birth defects with both Mendelian and complex etiologies. The phenotypic spectrum of OFCs may include overt clefts and several subclinical phenotypes, such as discontinuities in the orbicularis oris muscle (OOM) in the upper lip, velopharyngeal insufficiency (VPI), microform clefts or bifid uvulas. We hypothesize that expanding the OFC phenotype to include these phenotypes can clarify inheritance patterns in multiplex families, making them appear more Mendelian. We performed whole-exome sequencing to find rare, likely causal genetic variants in 31 multiplex OFC families, which included families with multiple individuals with OFCs and individuals with subclinical phenotypes. We identified likely causal variants in COL11A2, IRF6, KLF4, SHROOM3, SMC3, TP63 , and TBX3 in seven families. Although we did not find clear evidence supporting the subclinical phenotype hypothesis, our findings support a role for rare variants in the etiology of OFCs.

Prioritization of non-coding elements involved in non-syndromic cleft lip with/without cleft palate through genome-wide analysis of de novo mutations

Non-syndromic cleft lip with/without cleft palate (nsCL/P) is a highly heritable facial disorder. To date, systematic investigations of the contribution of rare variants in non-coding regions to nsCL/P etiology are sparse. Here, we re-analyzed available whole-genome sequence (WGS) data from 211 European case-parent trios with nsCL/P and identified 13,522 de novo mutations (DNMs) in nsCL/P cases, 13,055 of which mapped to non-coding regions. We integrated these data with DNMs from a reference cohort, with results of previous genome-wide association studies (GWASs), and functional and epigenetic datasets of relevance to embryonic facial development. A significant enrichment of nsCL/P DNMs was observed at two GWAS risk loci (4q28.1 (p = 8 × 10-4) and 2p21 (p = 0.02)), suggesting a convergence of both common and rare variants at these loci. We also mapped the DNMs to 810 position weight matrices indicative of transcription factor (TF) binding, and quantified the effect of the allelic changes in silico. This revealed a nominally significant overrepresentation of DNMs (p = 0.037), and a stronger effect on binding strength, for DNMs located in the sequence of the core binding region of the TF Musculin (MSC). Notably, MSC is involved in facial muscle development, together with a set of nsCL/P genes located at GWAS loci. Supported by additional results from single-cell transcriptomic data and molecular binding assays, this suggests that variation in MSC binding sites contributes to nsCL/P etiology. Our study describes a set of approaches that can be applied to increase the added value of WGS data.

Comparison of Presurgical Anthropometric Measures of Right and Left Complete Unilateral Cleft Lip and/or Palate

BACKGROUND

Left clefts occur twice as frequently as right ones. The sidedness has been suggested to influence certain outcomes. Some surgeons consider a right cleft more challenging to repair. This is often attributed to their reduced prevalence. The authors question whether this may be caused by morphologic differences. The authors' hypothesis is that there are anthropometric differences between left and right complete cleft lips.

METHODS

Patients with complete unilateral cleft lip, with or without cleft palate, operated on at the age of 3 to 6 months, between 2000 and 2018, by a single surgeon, were included. Eight standardized anthropometric measurements of the cleft lip, collected just before cleft lip repair, compare lip and vermillion dimensions and ratios between left and right clefts.

RESULTS

One hundred thirty-nine left and 80 right unilateral cleft lips were compared. A significant difference was found between left and right clefts for cleft-side to non-cleft-side ratios comparing the lateral lip element vertical heights and vermillion heights.

CONCLUSIONS

Patients with right cleft lips have a greater degree of lateral lip element hypoplasia, demonstrating greater deficiencies of lateral lip element vertical height and vermillion height when compared to patients with left clefts. This has clinical implications for preoperative assessment, choice of surgical technique, and postoperative and long-term outcomes.

Limb development genes underlie variation in human fingerprint patterns

Fingerprints are of long-standing practical and cultural interest, but little is known about the mechanisms that underlie their variation. Using genome-wide scans in Han Chinese cohorts, we identified 18 loci associated with fingerprint type across the digits, including a genetic basis for the long-recognized “pattern-block” correlations among the middle three digits. In particular, we identified a variant near EVI1 that alters regulatory activity and established a role for EVI1 in dermatoglyph patterning in mice. Dynamic EVI1 expression during human development supports its role in shaping the limbs and digits, rather than influencing skin patterning directly. Trans-ethnic meta-analysis identified 43 fingerprint-associated loci, with nearby genes being strongly enriched for general limb development pathways. We also found that fingerprint patterns were genetically correlated with hand proportions. Taken together, these findings support the key role of limb development genes in influencing the outcome of fingerprint patterning.

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GWAS identifies variants associated with fingerprint type across all digits

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Fingerprint-associated genes are strongly enriched for limb development functions

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Evi1 alters dermatoglyphs in mice by modulating limb rather than skin development

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Fingerprint patterns are genetically correlated with hand and finger proportions

Dental anomalies frequency in submucous cleft palate versus complete cleft palate

BACKGROUND/OBJECTIVES

This retrospective study evaluated the prevalence of dental anomalies of number in different subphenotypes of isolated cleft palate.

MATERIALS/METHODS

The sample comprised 26 individuals with submucous cleft palate (group S) and 68 individuals with complete cleft palate (group C) aged between 9 and 12 years from a single centre. Panoramic radiographs were evaluated regarding the presence of dental anomalies of number in permanent teeth. Intergroup comparison was performed using chi-square tests (P < 0.05).

RESULTS

Tooth agenesis was found in 34.61 and 36.76 per cent of group S and group C, respectively. The most commonly missing teeth were the maxillary second premolar, maxillary lateral incisor, and mandibular second premolar. Supernumerary teeth were found in none and 1.47 per cent of the individuals with submucous and complete cleft palate, respectively. No statistically significant difference was found between groups for the frequency of tooth agenesis and supernumerary teeth.

LIMITATIONS

Only dental anomalies of number were evaluated.

CONCLUSIONS/IMPLICATIONS

Individuals with submucous and complete cleft palate showed similar prevalence for tooth agenesis and supernumerary teeth. Dental anomalies frequency seems not to be a discriminator for subphenotypes of cleft palate.

The Intersection of the Genetic Architectures of Orofacial Clefts and Normal Facial Variation

Unaffected relatives of individuals with non-syndromic cleft lip with or without cleft palate (NSCL/P) show distinctive facial features. The presence of this facial endophenotype is potentially an expression of underlying genetic susceptibility to NSCL/P in the larger unselected population. To explore this hypothesis, we first partitioned the face into 63 partially overlapping regions representing global-to-local facial morphology and then defined endophenotypic traits by contrasting the 3D facial images from 264 unaffected parents of individuals with NSCL/P versus 3,171 controls. We observed distinct facial features between parents and controls across 59 global-to-local facial segments at nominal significance (p ≤ 0.05) and 52 segments at Bonferroni corrected significance (p < 1.2 × 10-3), respectively. Next, we quantified these distinct facial features as univariate traits in another dataset of 8,246 unaffected European individuals and performed a genome-wide association study. We identified 29 independent genetic loci that were associated (p < 5 × 10-8) with at least one of the tested endophenotypic traits, and nine genetic loci also passed the study-wide threshold (p < 8.47 × 10-10). Of the 29 loci, 22 were in proximity of loci previously associated with normal facial variation, 18 were near genes that show strong evidence in orofacial clefting (OFC), and another 10 showed some evidence in OFC. Additionally, polygenic risk scores for NSCL/P showed associations with the endophenotypic traits. This study thus supports the hypothesis of a shared genetic architecture of normal facial development and OFC.

Dental Subphenotypes in Infants With Orofacial Clefts-A Longitudinal Population-Based Retrospective Radiographic Study of the Primary and Secondary Dentitions

OBJECTIVES

To determine the developmental patterns of primary and secondary dentitions in infants with orofacial clefts.

DESIGN

Retrospective, longitudinal, population-based cohort study.

MATERIALS

Longitudinal records and radiographs of 192 nonsyndromic Northern European infants with isolated unilateral cleft lip (UCL, n = 111) and isolated cleft palate (CP, n = 81).

METHODS

Radiographic assessments of primary and secondary dentition anomalies and dental maturation, by gender and cleft severity for comparisons between the groups and with historical controls.

RESULTS

In infants with UCL, the frequencies of dental anomalies were high in both primary (38.7%) and secondary (18.0%) dentitions. Primary and secondary dentition anomalies were not observed in infants with CP and different in the UCL group (P = .003). Risk differences involved primary supernumerary teeth (P = .0001) and talon cusp formation (P = .0001), and secondary tooth agenesis (P = .001) of the maxillary lateral incisor on the side of the cleft lip. Delayed primary and secondary dental maturation occurred in the UCL and CP groups, greater in infants with UCL (P < .0001). Primary and secondary dental maturation featured sexual dimorphism with greater delay in males (UCL, P < .0001; CP, .0001 > P = .001). The effect of cleft severity on dental maturation was significant in infants with UCL (P = .0361) and CP (P = .0175) in the primary but not in the secondary dentition.

CONCLUSIONS

There were different dental anomalies in the primary and secondary dentitions in operated infants with UCL and no dental anomalies in unoperated infants with CP. Dental maturation was delayed in infants with UCL and CP with greater delay in males compared to females.

Derecho a la atención sanitaria para madres y menores de 18 años afectados con labio y/o paladar hendido en República Dominicana

Objetivo: identificar y describir, desde la perspectiva del derecho fundamental a la salud, la garantía de la atención sanitaria en menores dominicanos afectados con labio y/o paladar hendido (LPH) y sus madres. Métodos: en tanto este es un estudio descriptivo, se realizaron encuestas semiestructuradas y se aplicó la observación no participante en los territorios de residencia de familias con menores afectados por LPH, atendidos en una fundación de República Dominicana. Resultados: la mayoría de familias afectadas por LPH pertenecen a clases sociales vulnerables con limitada capacidad de pago para adquirir seguros de salud. De las 39 familias abordadas, 26 madres no contaron con seguro de salud durante la gestación, pero los 39 pacientes con LPH sí contaban con algún tipo de aseguramiento. Se evidenció negación sistemática en la prestación de  servicios sanitarios, barreras administrativas, invisibilización de la problemática del LPH en los servicios de salud y en definitiva, un sistema de salud excluyente en la práctica. Conclusión: pese a que la atención sanitaria a gestantes y menores de 18 años se reconoce constitucionalmente como un derecho fundamental a cargo del Estado, la forma en que opera el sistema de salud dominicano supedita la atención a la capacidad de pago de las familias, lo que genera inequidades sociales y sanitarias que vulneran el goce efectivo del derecho a la salud de las madres y los menores que nacen con LPH. 

Individuals with nonsyndromic orofacial clefts have increased asymmetry of fingerprint patterns

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.

Association between MSX1 rs12532 polymorphism with nonsyndromic unilateral complete cleft lip and palate and tooth agenesis

OBJECTIVES

To investigate the association of MSX1 rs12532 polymorphism with the risk of nonsyndromic unilateral complete cleft lip and palate (NSCLP) and tooth agenesis.

MATERIALS AND METHODS

The study is comprised of 384 individuals divided into 4 groups: group 1, patients with unilateral complete NSCLP and premolar agenesis (n = 57); group 2, patients with unilateral NSCLP without tooth agenesis (n = 117); group 3, patients with premolar agenesis without oral cleft (n = 53) and group 4 (n = 157), a control group with individuals without tooth agenesis and oral cleft. Genotyping of rs12532 was carried out with Taqman chemistry, and associations were investigated using logistic regression analyses.

RESULTS

Overall rs12532 allele and genotype distributions revealed no significant differences between the groups of NSCLP or tooth agenesis.

CONCLUSION

Although our results are consistent with a lack of association of MSX1 rs12532 and the risk of unilateral NSCLP and tooth agenesis, further studies with additional SNPs and a more diverse ethnic cohort are warranted.

Speech Phenotyping in Unaffected Family Members of Individuals With Nonsyndromic Cleft Lip With or Without Palate

OBJECTIVE

Subclinical phenotypes of nonsyndromic cleft lip with or without cleft palate (CL ± P) may be identified from clinically "unaffected" relatives and could be associated with specific cleft-related gene mutations. It has been hypothesized that velopharyngeal insufficiency (VPI) may be a subclinical phenotype of interest in this population, but this has not been explored quantitatively with appropriate control cohorts. The aim of this case-control study was to compare VPI in at-risk clinically unaffected relatives of individuals with nonsyndromic CL ± P with a low-risk matched normative Australian cohort.

PARTICIPANTS

Clinically unaffected (ie, with no overt cleft) first-degree relatives of a proband with nonsyndromic CL ± P (n = 189) and noncleft controls (n = 207).

MAIN OUTCOME MEASURE(S)

Perceptual measures of VPI encompassing resonance, nasal emission, and articulation were evaluated using the Great Ormond Street Speech Assessment. Quantitative measures of VPI were obtained from the Nasometer II using standardized adult and pediatric speech stimuli.

RESULTS

Both perceptual and instrumental measures showed no significant difference (P > .01) between the VPI in unaffected relatives and the noncleft comparison group. Mean nasalance scores for both groups were calculated and reported according to speech stimuli, age, and sex.

CONCLUSIONS

Results suggest that VPI, measured through speech, is not a significant subclinical phenotype of nonsyndromic CL ± P. Therefore, further familial genetic investigations exploring VPI may not yield meaningful results. Exploration across multiple subclinical phenotypes in larger cohorts may enable researchers to better understand the multifaceted nature of this complex and heterogeneous anomaly.

One-Stage versus Two-Stage Repair of Asymmetric Bilateral Cleft Lip: A 20-Year Retrospective Study of Clinical Outcome

BACKGROUND

Both one- and two-stage approaches have been widely used for patients with asymmetric bilateral cleft lip. There are insufficient long-term outcome data for comparison of these two methods. The purpose of this retrospective study was to compare the clinical outcome over the past 20 years.

METHODS

The senior author's (L.J.L.) database was searched for patients with asymmetric bilateral cleft lip from 1995 to 2015. Qualified patients were divided into two groups: one-stage and two-stage. The postoperative photographs of patients were evaluated subjectively by surgical professionals and laypersons. Ratios of the nasolabial region were calculated for objective analysis. Finally, the revision procedures in the nasolabial area were reviewed. Statistical analyses were performed.

RESULTS

A total of 95 consecutive patients were qualified for evaluation. Average follow-up was 13.1 years. A two-stage method was used in 35 percent of the patients, and a one-stage approach was used in 65 percent. All underwent primary nasal reconstruction. Among the satisfaction rating scores, the one-stage repair was rated significantly higher than two-stage reconstruction (p = 0.0001). Long-term outcomes of the two-stage patients and the unrepaired mini-microform deformities were unsatisfactory according to both professional and nonprofessional evaluators. The revision rate was higher in patients with a greater-side complete cleft lip and palate as compared with those without palatal involvement.

CONCLUSIONS

The results suggested that one-stage repair provided better results with regard to achieving a more symmetric and smooth lip and nose after primary reconstruction. The revision rate was slightly higher in the two-stage patient group.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

GWAS reveals loci associated with velopharyngeal dysfunction

Velopharyngeal dysfunction (VPD) occurs when the muscular soft palate (velum) and lateral pharyngeal walls are physically unable to separate the oral and nasal cavities during speech production leading to hypernasality and abnormal speech reduction. Because VPD is often associated with overt or submucous cleft palate, it could be present as a subclinical phenotype in families with a history of orofacial clefting. A key assumption to this model is that the overt and subclinical manifestations of the orofacial cleft phenotype exist on a continuum and therefore share common etiological factors. We performed a genome-wide association study in 976 unaffected relatives of isolated CP probands, 54 of whom had VPD. Five loci were significantly (p < 5 × 10^-8) associated with VPD: 3q29, 9p21.1, 12q21.31, 16p12.3 and 16p13.3. An additional 15 loci showing suggestive evidence of association with VPD were observed. Several genes known to be involved in orofacial clefting and craniofacial development are located in these regions, such as TFRC, PCYT1A, BNC2 and FREM1. Although further research is necessary, this could be an indication for a potential shared genetic architecture between VPD and cleft palate, and supporting the hypothesis that VPD is a subclinical phenotype of orofacial clefting.

Mapping genetic variants for cranial vault shape in humans

The shape of the cranial vault, a region comprising interlocking flat bones surrounding the cerebral cortex, varies considerably in humans. Strongly influenced by brain size and shape, cranial vault morphology has both clinical and evolutionary relevance. However, little is known about the genetic basis of normal vault shape in humans. We performed a genome-wide association study (GWAS) on three vault measures (maximum cranial width [MCW], maximum cranial length [MCL], and cephalic index [CI]) in a sample of 4419 healthy individuals of European ancestry. All measures were adjusted by sex, age, and body size, then tested for association with genetic variants spanning the genome. GWAS results for the two cohorts were combined via meta-analysis. Significant associations were observed at two loci: 15p11.2 (lead SNP rs2924767, p = 2.107 × 10⁻⁸) for MCW and 17q11.2 (lead SNP rs72841279, p = 5.29 × 10⁻⁹) for MCL. Additionally, 32 suggestive loci (p < 5x10^-6) were observed. Several candidate genes were located in these loci, such as NLK, MEF2A, SOX9 and SOX11. Genome-wide linkage analysis of cranial vault shape in mice (N = 433) was performed to follow-up the associated candidate loci identified in the human GWAS. Two loci, 17q11.2 (c11.loc44 in mice) and 17q25.1 (c11.loc74 in mice), associated with cranial vault size in humans, were also linked with cranial vault size in mice (LOD scores: 3.37 and 3.79 respectively). These results provide further insight into genetic pathways and mechanisms underlying normal variation in human craniofacial 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.

Analysis of Parent-of-Origin Effects on the X Chromosome in Asian and European Orofacial Cleft Triads Identifies Associations with DMD, FGF13, EGFL6, and Additional Loci at Xp22.2

Background: Although both the mother's and father's alleles are present in the offspring, they may not operate at the same level. These parent-of-origin (PoO) effects have not yet been explored on the X chromosome, which motivated us to develop new methods for detecting such effects. Orofacial clefts (OFCs) exhibit sex-specific differences in prevalence and are examples of traits where a search for various types of effects on the X chromosome might be relevant. Materials and Methods: We upgraded our R-package Haplin to enable genome-wide analyses of PoO effects, as well as power simulations for different statistical models. 14,486 X-chromosome SNPs in 1,291 Asian and 1,118 European case-parent triads of isolated OFCs were available from a previous GWAS. For each ethnicity, cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO) were analyzed separately using two X-inactivation models and a sliding-window approach to haplotype analysis. In addition, we performed analyses restricted to female offspring. Results: Associations were identified in "Dystrophin" (DMD, Xp21.2-p21.1), "Fibroblast growth factor 13" (FGF13, Xq26.3-q27.1) and "EGF-like domain multiple 6" (EGFL6, Xp22.2), with biologically plausible links to OFCs. Unlike EGFL6, the other associations on chromosomal region Xp22.2 had no apparent connections to OFCs. However, the Xp22.2 region itself is of potential interest because it contains genes for clefting syndromes [for example, "Oral-facial-digital syndrome 1" (OFD1) and "Midline 1" (MID1)]. Overall, the identified associations were highly specific for ethnicity, cleft subtype and X-inactivation model, except for DMD in which associations were identified in both CPO and CL/P, in the model with X-inactivation and in Europeans only. Discussion/Conclusion: The specificity of the associations for ethnicity, cleft subtype and X-inactivation model underscores the utility of conducting subanalyses, despite the ensuing need to adjust for additional multiple testing. Further investigations are needed to confirm the associations with DMD, EGF16, and FGF13. Furthermore, chromosomal region Xp22.2 appears to be a hotspot for genes implicated in clefting syndromes and thus constitutes an exciting direction to pursue in future OFCs research. More generally, the new methods presented here are readily adaptable to the study of X-linked PoO effects in other outcomes that use a family-based design.

Muscle fiber diameter assessment in cleft lip using image processing

OBJECTIVE

To pilot investigation of muscle fiber diameter (MFD) on medial and lateral sides of the cleft in 18 infants with cleft lip with or without cleft palate (CL/P) using image processing.

MATERIAL AND METHODS

Formalin-fixed paraffin-embedded (FFPE) tissue samples from the medial and lateral sides of the cleft were analyzed for MFD using an image-processing program (ImageJ). For within-case comparison, a paired Student's t test was performed. For comparisons between classes, an unpaired t test was used.

RESULTS

Image processing enabled rapid measurement of MFD with majority of fibers showing diameter between 6 and 11 μm. There was no significant difference in mean MFD between the medial and lateral sides, or between CL and CLP. However, we found a significant difference on the medial side (p = .032) between males and females.

CONCLUSION

The image processing on FFPE tissues resulted in easy quantification of MFD with finding of a smaller MFD on the medial side in males suggesting possible differences in orbicularis oris (OO) muscle between the two sexes in CL that warrants replication using larger number of cases. Moreover, this finding can aid subclinical phenotyping and potentially in the restoration of the anatomy and function of the upper lip.

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.

Dental Decay Phenotype in Nonsyndromic Orofacial Clefting

Although children with oral clefts have a higher risk for dental anomalies when compared with the general population, prior studies have shown conflicting results regarding their dental decay risk. Also, few studies have assessed dental decay risk in unaffected relatives of children with clefts. Thus, the question of increased risk of dental decay in individuals with oral clefts or their unaffected relatives is still open for empirical investigation. This study characterizes dental decay in the largest international cohort to date of children with nonsyndromic clefts and their relatives, as compared with controls, and it addresses whether families with oral clefts have a significantly increased risk for dental decay versus the general population. A total of 3,326 subjects were included: 639 case probands, 1,549 unaffected relatives, and 1,138 controls. Decay was identified from in-person dental examinations or intraoral photographs. Case-control differences were tested with regression analysis. No significant differences were shown in percentage decayed and filled teeth and decayed teeth in the primary dentition (dft, dt) and permanent dentition (DFT, DT) in cases versus controls. In the cleft region, no significant differences were seen in primary or permanent decay (dt, DT) when compared with controls. No difference was found with regard to cleft type and percentage dft, dt, DFT, and DT in case probands. Nonsignificant differences were found in unaffected siblings and parents versus controls (primary and permanent dentitions). Collectively, these findings indicate that individuals with nonsyndromic oral clefts and their families do not have a higher dental decay risk as compared with the general population. These results suggest that either genetic or environmental factors underlying a higher susceptibility for dental anomalies do not increase caries risk or that the seemingly higher risk for dental decay associated with increased dental anomalies in case probands may be superseded by possible greater access to dental care.

Laterality of Oral Clefts and Academic Achievement

BACKGROUND AND OBJECTIVES

Children with isolated oral clefts have lower academic performance when compared with unaffected peers, yet few studies have examined specific attributes of clefts that may modify this risk. Oral clefts have nonrandom laterality, with left-sided clefts being more common than right-sided clefts, a pattern that may be genetically or environmentally influenced. The objective of this study was to evaluate the association between cleft laterality and academic achievement in a population-based sample of children with and without isolated oral clefts.

METHODS

The study included 292 children with isolated unilateral cleft lip with or without cleft palate identified by using the Iowa Registry for Congenital and Inherited Disorders matched with 908 unaffected classmates. This group provided 1953 child-grade observations for cases and 6829 for classmates. Academic achievement was evaluated by using high-quality standardized test data on multiple academic domains as well as use of special education.

RESULTS

We found that children with right-sided clefts had similar achievement scores and usage of special education services compared with their unaffected classmates. Children with left-sided clefts had lower reading scores than children with right-sided clefts by nearly 7 percentiles (P < .05). They also had lower scores on all evaluated domains by 4 to 6 percentiles and greater use of special education services by 6 percentage points than their classmates.

CONCLUSIONS

Children with left-sided clefts had poorer academic performance than their classmates or children with right-sided clefts, who showed similar academic achievement compared with their unaffected classmates.

Hypertelorism and Orofacial Clefting Revisited: An Anthropometric Investigation

OBJECTIVE

Since the 1960s, multiple studies have reported a tendency toward hypertelorism in individuals with nonsyndromic orofacial clefts (OFCs). However, the association between specific cleft types and increased interorbital distance has been inconsistent. Using three-dimensional (3D) surface imaging, we tested whether different forms of clefting showed evidence of increased interorbital distance.

METHODS

Intercanthal and outercanthal distances and intercanthal indices were calculated from 3D facial surface images of 287 individuals with repaired OFCs. Raw measurements were converted to sex and age-normalized Z-scores. Mean Z-scores for individuals with cleft lip (CL), cleft lip and palate (CLP), and cleft palate (CP) were compared with reference normative values (controls) and one another directly using t tests and analysis of variance.

RESULTS

The CLP group showed a significant increase in intercanthal width (P = .001) and intercanthal index (P < .001) compared with reference norms. The CP group showed a significant decrease (P < .001) in outercanthal width. The CL group showed no difference from reference norms. The proportion of clinically hyperteloric individuals was generally low but highest in the CLP group (7.4%). Cleft severity had little effect on interorbital spacing.

CONCLUSIONS

Individuals with CLP exhibited on average a tendency toward mild hypertelorism, driven primarily by an increase in intercanthal distance. This tendency was not seen in CL or CP.

Using Whole Exome Sequencing to Identify Candidate Genes With Rare Variants In Nonsyndromic Cleft Lip and Palate

Studies suggest that nonsyndromic cleft lip and palate (NSCLP) is polygenic with variable penetrance, presenting a challenge in identifying all causal genetic variants. Despite relatively high prevalence of NSCLP among Amerindian populations, no large whole exome sequencing (WES) studies have been completed in this population. Our goal was to identify candidate genes with rare genetic variants for NSCLP in a Honduran population using WES. WES was performed on two to four members of 27 multiplex Honduran families. Genetic variants with a minor allele frequency > 1% in reference databases were removed. Heterozygous variants consistent with dominant disease with incomplete penetrance were ascertained, and variants with predicted functional consequence were prioritized for analysis. Pedigree-specific P-values were calculated as the probability of all affected members in the pedigree being carriers, given that at least one is a carrier. Preliminary results identified 3,727 heterozygous rare variants; 1,282 were predicted to be functionally consequential. Twenty-three genes had variants of interest in ≥3 families, where some genes had different variants in each family, giving a total of 50 variants. Variant validation via Sanger sequencing of the families and unrelated unaffected controls excluded variants that were sequencing errors or common variants not in databases, leaving four genes with candidate variants in ≥3 families. Of these, candidate variants in two genes consistently segregate with NSCLP as a dominant variant with incomplete penetrance: ACSS2 and PHYH. Rare variants found at the same gene in all affected individuals in several families are likely to be directly related to NSCLP.

Exploring Subclinical Phenotypic Features in Twin Pairs Discordant for Cleft Lip and Palate

OBJECTIVE

Monozygotic twins of an individual with an orofacial cleft have a significantly elevated risk for orofacial cleft compared with the general population, but still the concordance rate for orofacial cleft in monozygotic twins is about 40% to 50%. The goal of this study was to determine whether unaffected cotwins have an increased frequency of orbicularis oris muscle defects, a subclinical form of orofacial cleft. The presence of such defects may reduce the overall rate of discordance.

METHOD

A total of 63 discordant monozygotic and dizygotic twin pairs, 262 unaffected nontwin siblings, and 543 controls with no history of orofacial clefts were assessed for orbicularis oris defects by high-resolution ultrasound. Frequencies were compared by the Fisher exact test.

RESULTS

Unaffected cotwins from discordant monozygotic pairs had a higher frequency of defects (12.5%) than the other test groups (6.38% to 6.99%), but the difference was not statistically significant (P = .74).

CONCLUSIONS

In this study, orbicularis oris defects were not statistically significantly more common among the unaffected twins from orofacial cleft discordant twin pairs. The trends in the results warrant future studies with larger sample sizes and additional subclinical phenotypes.

Spectrum of Dental Phenotypes in Nonsyndromic Orofacial Clefting

Children with oral clefts show a wide range of dental anomalies, adding complexity to understanding the phenotypic spectrum of orofacial clefting. The evidence is mixed, however, on whether the prevalence of dental anomalies is elevated in unaffected relatives and is mostly based on small samples. In the largest international cohort to date of children with nonsyndromic clefts, their relatives, and controls, this study characterizes the spectrum of cleft-related dental anomalies and evaluates whether families with clefting have a significantly higher risk for such anomalies compared with the general population. A total of 3,811 individuals were included: 660 cases with clefts, 1,922 unaffected relatives, and 1,229 controls. Dental anomalies were identified from in-person dental exams or intraoral photographs, and case-control differences were tested using χ(2) statistics. Cases had higher rates of dental anomalies in the maxillary arch than did controls for primary (21% vs. 4%, P = 3 × 10(-8)) and permanent dentitions (51% vs. 8%, P = 4 × 10(-62)) but not in the mandible. Dental anomalies were more prevalent in cleft lip with cleft palate than other cleft types. More anomalies were seen in the ipsilateral side of the cleft. Agenesis and tooth displacements were the most common dental anomalies found in case probands for primary and permanent dentitions. Compared with controls, unaffected siblings (10% vs. 2%, P = 0.003) and parents (13% vs. 7%, P = 0.001) showed a trend for increased anomalies of the maxillary permanent dentition. Yet, these differences were nonsignificant after multiple-testing correction, suggesting genetic heterogeneity in some families carrying susceptibility to both overt clefts and dental anomalies. Collectively, the findings suggest that most affected families do not have higher genetic risk for dental anomalies than the general population and that the higher prevalence of anomalies in cases is primarily a physical consequence of the cleft and surgical interventions.

Ear Infection in Isolated Cleft Lip: Etiological Implications

BACKGROUND AND HYPOTHESIS

Chronic ear infections are a common occurrence in children with orofacial clefts involving the secondary palate. Less is known about the middle ear status of individuals with isolated clefts of the lip, although several studies have reported elevated rates of ear infection in this group. The purpose of this retrospective study was to test the hypothesis that chronic ear infections occur more frequently in isolated cleft lip cases (n = 94) compared with controls (n = 183).

METHODS

A questionnaire was used to obtain information on history of chronic ear infection. The association between ear infection status (present/absent) and cleft lip status (cleft lip case/control) was tested using both chi-square and logistic regression.

RESULTS AND CONCLUSIONS

The reported occurrence of chronic ear infection was significantly greater in cleft lip cases (31%) compared with unaffected controls (11%). After adjusting for age and sex, having a cleft lip increased the odds of being positive for ear infection by a factor greater than 3 (odds ratio = 3.698; 95% confidence interval = 1.91 to 7.14). Within cleft lip cases, there was no difference in the occurrence of ear infection by defect laterality or by the type of clefting present in the family history. Although velopharyngeal insufficiency was present in 18.4% of our cleft lip sample, there was no statistical association between ear infection and abnormal speech patterns. These results may have potential implications both for the clinical management of isolated cleft lip cases and for understanding the etiology of orofacial clefting.

Presurgical Unilateral Cleft Lip Anthropometrics and the Presence of Dental Anomalies

Objective

To investigate associations between cleft lip anthropometrics and dental anomalies in the permanent dentition in unilateral cleft lip patients.

Design

Retrospective cross-sectional study.

Patients

Children with unilateral clefts of the lip, with or without cleft palate.

Methods

Anthropometric lip measurements, made immediately prior to lip repair, were available for each patient. The presence of dental anomalies in the permanent dentition was assessed radiographically. The presence of associations between anthropometric lip measurements and prevalence rates of different dental anomalies were determined using logistic regression analyses.

Results

In the 122 included patients, the cleft lateral lip element was deficient in height in 80% and in transverse length in 84% of patients. Patients with more deficient cleft side lateral lip height and less deficient cleft side lateral lip transverse length were more likely to present with cleft side maxillary lateral incisor agenesis. On the other hand, patients with a less deficient cleft side lateral lip height and more deficient cleft side lateral lip transverse length were more likely to present with a cleft side supernumerary maxillary lateral incisor. When looking only at incomplete clefts, the cleft side lateral lip transverse length deficiency was more predictive of the presence of supernumerary maxillary lateral incisors (P= .030), while for complete clefts, the cleft side lateral lip height deficiency was more predictive of the presence of maxillary lateral incisor agenesis ( P = .035).

Conclusions

In patients with unilateral clefts, cleft lip anthropometrics have a predictive role in determining the occurrence of dental anomalies.

Evaluating fluctuating asymmetry in a Brazilian population with non-syndromic cleft lip and/or palate

OBJECTIVE

The objective of this work was to analyse the levels of dermatoglyphic asymmetry between both parents and individuals with non-syndromic cleft lip and/or palate (NSCL/P) and unaffected control trios.

METHODS

A case-control analysis was carried out of 51 affected trios (unaffected parents and NSCL/P subjects), and 50 unaffected control trios. Finger and palm prints were taken from each participant, and dermatoglyphic patterns, the number of lines on the digits, and the palmar angles were recorded. To determine the level of fluctuating asymmetry the case group was compared with the control group, significance accepted at p ≤ 0.05.

RESULTS

There was a statistically significant difference between the atd angles (angle between the lines triradii a and t and triradii t and d) of fathers of those affected by NSCL/P, and the dermatoglyphic patterns of the affected mothers, with significantly more arches in the control group. However, in this study, multiple comparisons were used, and the results must be evaluated as initial findings and evaluated carefully since the significance disappears after correction for multiple comparisons. Other parameters did not differ between groups. There was no difference in parameters among patients affected by NSCL/P.

CONCLUSIONS

Based on these results it is speculated that the mechanisms responsible for the formation of NSCL/P may be associated with those responsible for deviations in the asymmetry of the atd angles in the fathers and dermatoglyphic patterns of the mothers of affected patients. Besides, further studies are required to determine the real relationship between these conditions.

Evidence of olfactory deficits as part of the phenotypic spectrum of nonsyndromic orofacial clefting

Improved understanding of the phenotypic spectrum associated with nonsyndromic orofacial clefting (OFC) has the potential to inform efforts to uncover the etiology of this complex trait. Prior studies report that individuals with OFC are characterized by impaired olfactory ability. In this study, we test whether olfactory dysfunction extends to the unaffected parents of children with OFC. The University of Pennsylvania Smell Identification Test was used to measure olfactory ability in a sample of 60 unaffected mothers and fathers with cleft-affected children. The proportion of deficit was compared with reference data obtained from published sex- and age-specific norms on more than 2700 individuals. The proportion of deficit was significantly higher in unaffected parents compared with baseline control subjects (41.7% vs 12.6%; P < 0.001). Of unaffected fathers, 41.7% displayed evidence of deficit compared with 15.1% of male control subjects (P = 0.001), whereas 41.7% of mothers exhibited deficits compared with 10.4% of female control subjects (P < 0.001). Olfactory deficits are present at a high proportion in the unaffected parents of individuals with OFC. This suggests that the deficits observed in affected cases may not simply be a secondary consequence of surgical repair and may instead be an informative phenotype reflecting underlying etiology.

Facial morphometrics of children with non-syndromic orofacial clefts in Tanzania

Background

Orofacial clefts (cleft lip/palate; CL/P) are among the most common congenital anomalies, with prevalence that varies among different ethnic groups. Craniofacial shape differences between individuals with CL/P and healthy controls have been widely reported in non-African populations. Knowledge of craniofacial shape among individuals with non-syndromic CL/P in African populations will provide further understanding of the ethnic and phenotypic variation present in non-syndromic orofacial clefts.

Methods

A descriptive cross-sectional study was carried out at Bugando Medical Centre, Tanzania, comparing individuals with unrepaired non-syndromic CL/P and normal individuals without orofacial clefts. Three-dimensional (3D) facial surfaces were captured using a non-invasive 3D camera. The corresponding 3D coordinates for 26 soft tissue landmarks were used to characterize facial shape. Facial shape variation within and between groups, based on Procrustes superimposed data, was studied using geometric morphometric methods.

Results

Facial shape of children with cleft lip differed significantly from the control group, beyond the cleft itself. The CL/P group exhibited increased nasal and mouth width, increased interorbital distance, and more prognathic premaxillary region. Within the CL/P group, PCA showed that facial shape variation is associated with facial height, nasal cavity width, interorbital distance and midfacial prognathism. The isolated cleft lip (CL) and combined cleft lip and palate (CLP) groups did not differ significantly from one another (Procrustes distance = 0.0416, p = 0.50). Procrustes distance permutation tests within the CL/P group showed a significant shape difference between unilateral clefts and bilateral clefts (Procrustes distance = 0.0728, p = 0.0001). Our findings indicate the morphological variation is similar to those of studies of CL/P patients and their unaffected close relatives in non-African populations.

Conclusion

The mean facial shape in African children with non-syndromic CL/P differs significantly from children without orofacial clefts. The main differences involve interorbital width, facial width and midface prognathism. The axes of facial shape differences we observed are similar to the patterns seen in Caucasian populations, despite apparent differences in cleft prevalence and cleft type distribution. Similar facial morphology in individuals with CL/P in African and Caucasian populations suggests a similar aetiology.

Expanding the cleft phenotype: the dental characteristics of unaffected parents of Australian children with non-syndromic cleft lip and palate

BACKGROUND

The aetiology of isolated clefts of the lip and/or palate remains obscure. Unaffected family members are treated as if their genetic risks are equivalent and low. Given the number of genes associated with both clefting and dental anomalies, the hypothesis that such anomalies contribute to the cleft phenotype should be explored.

AIM

To describe the dental characteristics of parents of children with non-syndromic cleft lip ± palate.

DESIGN

Unaffected parents of Australian children with a cleft of the lip ± palate underwent dental examination including radiographs, photographs, and impressions. Dental anomalies were identified.

RESULTS

Data were available on 101 parents (49 males, 52 females). Fifty-one participants had at least one dental anomaly. Twelve (11.8%) individuals had congenital absence of teeth, with seven missing multiple teeth. The tooth most commonly missing was the upper right lateral incisor. Five subjects (4.9%) had microdontia (upper lateral incisor most commonly affected). Four subjects (4.0%) had supernumerary teeth. Enamel defects were present in 27 (26.7%) cases with the incisors (46.8%) followed by premolars (24.2%) most affected.

CONCLUSIONS

This study supports previous work suggesting that 'unaffected' parents of children with clefts of the lip ± palate may present with dental anomalies.

Exploratory genotype-phenotype correlations of facial form and asymmetry in unaffected relatives of children with non-syndromic cleft lip and/or palate

Family relatives of children with nonsyndromic cleft lip with or without cleft palate (NSCL/P) who presumably carry a genetic risk yet do not manifest overt oral clefts, often present with distinct facial morphology of unknown genetic etiology. This study investigates distinct facial morphology among unaffected relatives and examines whether candidate genes previously associated with overt NSCL/P and left-right body patterning are correlated with such facial morphology. Cases were unaffected relatives of individuals with NSCL/P (n = 188) and controls (n = 194) were individuals without family history of NSCL/P. Cases and controls were genotyped for 20 SNPs across 13 candidate genes for NSCL/P (PAX7, ABCA4-ARHGAP29, IRF6, MSX1, PITX2, 8q24, FOXE1, TGFB3 and MAFB) and left-right body patterning (LEFTY1, LEFTY2, ISL1 and SNAI1). Facial shape and asymmetry phenotypes were obtained via principal component analyses and Procrustes analysis of variance from 32 coordinate landmarks, digitized on 3D facial images. Case-control comparisons of phenotypes obtained were performed via multivariate regression adjusting for age and gender. Phenotypes that differed significantly (P < 0.05) between cases and controls were regressed on the SNPs one at a time. Cases had significantly (P < 0.05) more profile concavity with upper face retrusion, upturned noses with obtuse nasolabial angles, more protrusive chins, increased lower facial heights, thinner and more retrusive lips and more protrusive foreheads. Furthermore, cases showed significantly more directional asymmetry compared to controls. Several of these phenotypes were significantly associated with genetic variants (P < 0.05). Facial height and width were associated with SNAI1. Midface antero-posterior (AP) projection was associated with LEFTY1. The AP position of the chin was related to SNAI1, IRF6, MSX1 and MAFB. The AP position of the forehead and the width of the mouth were associated with ABCA4-ARHGAP29 and MAFB. Lastly, facial asymmetry was related to LEFTY1, LEFTY2 and SNAI1. This study demonstrates that, genes underlying lip and palate formation and left-right patterning also contribute to facial features characteristic of the NSCL/P spectrum.

A comparative study of fluctuating asymmetry in Chinese families with nonsyndromic cleft palate

OBJECTIVE

To compare the asymmetry displayed by Chinese patients with nonsyndromic cleft palate (NSCP), their unaffected parents, and a control population.

METHOD

With rigorous inclusion criteria, a total number of 675 individuals with NSCP, 675 parental pairs of these patients, and 650 control individuals were involved in this case-control study. Size-adjusted fluctuating asymmetry (FA) scores were calculated by data on 10 variables. Analysis of variance was used for a three-way comparison of patients/gender-matched parents/gender-matched controls.

RESULTS

A significant increase in FA for ear length (p<.05) was noted in NSCP patients when compared with their gender-matched parents. A significant increase in FA for ear length and palpebral fissure width (p<.05) was observed in NSCP patients when compared with the gender-matched control population. A significant increase in FA for palpebral fissure width (p<.05) was detected in parents of NSCP patients when compared with a gender-matched control population.

CONCLUSION

Our results indicated that, when compared with a gender-matched control population, patients with NSCP show significantly increased FA in both ear length and palpebral fissure width, but the parents of patients with NSCP show significantly increased FA only in palpebral fissure width. In general, these characteristics seem to be more distinct in male individuals.

The impact of participation in genetic research for families with cleft lip with and without cleft palate: a qualitative study

Despite being the most common congenital facial anomaly, little is understood about the genetic contribution to isolated clefts of the lip with or without cleft palate (CL/P). 'OzCleft', a family-based genotype/phenotype study, is investigating this further. Participation for families involves various clinical investigations of the child with the cleft, and their unaffected sibling(s) and parents. Informal feedback from individuals involved in OzCleft suggested that participation in this research programme had benefits for families. Taking a qualitative approach, this study sought to investigate this hypothesis further. Semi-structured in-depth interviews were conducted with nine parents who had participated in OzCleft. All parents described participation as a positive experience for themselves and their families. Perceived benefits included a greater appreciation of the cleft treatment experience by unaffected family members. Being involved in a genetic study raised issues for parents regarding the cause of clefting in their child. While some parents found the possibility of a genetic component reassuring, it also raised questions about the potential implications for future generations. Parents were largely unsure about how to communicate this information to their children and the predictive value of this information. This study suggests a lack of genetic understanding and/or perceived value of genetic information by parents of children with CL/P that, in turn, highlights the need for increased support from genetic health professionals in this area.

Corpus callosum shape is altered in individuals with nonsyndromic cleft lip and palate

Individuals with nonsyndromic cleft lip with or without cleft palate (CL/P) have altered brain structure compared with healthy controls. Preliminary evidence suggests that the corpus callosum may be dysmorphic in orofacial clefting; however, this midline brain structure has not been systematically assessed in this population. The goal of the present study was to carry out a morphometric assessment of the corpus callosum and its relationship to cognitive performance in a well-characterized patient cohort with orofacial cleft. Midline brain images were obtained from previously collected MRI scans of 24 CL/P subjects and 40-adult-male controls. Eight landmarks on the corpus callosum were digitized on each image and their x,y coordinate locations saved. A geometric morphometrics analysis was applied to the landmark coordinate data to test for shape differences across groups. The relationship between corpus callosum shape and IQ was explored with nonparametric correlation coefficients. Results revealed significant differences in mean corpus callosum shape between CL/P cases and controls (P = 0.029). The CL/P corpus callosum was characterized by increased overall convexity resulting from a superior and posterior displacement. Within CL/P cases, increased corpus callosum shape dysmorphology was moderately correlated with reduced performance IQ (r = 0.546). These results provide additional evidence that midline brain changes may be an important part of the orofacial cleft phenotype.

Is missing maxillary lateral incisor in complete cleft lip and palate a product of genetics or local environment?

OBJECTIVE

To test the null hypothesis: Subjects with isolated complete unilateral cleft lip and palate (UCLP) show no differences in overall frequency of tooth agenesis (hypodontia), comparing a subsample with cleft-side maxillary lateral incisor (MxI2) agenesis to a subsample without cleft-side MxI2 agenesis. Findings could clarify the origins of cleft-side MxI2 agenesis.

MATERIALS AND METHODS

Tooth agenesis was identified from dental radiographs of 141 subjects with UCLP. The UCLP cohort was segregated into four categories according to the status and location of MxI2 in the region of the unilateral cleft: group M: subjects with one tooth, located on the mesial side of the alveolar cleft; group D: subjects with one tooth, located on the distal side of the alveolar cleft; group MD: subjects with two teeth present, one mesial and one distal to the cleft; and group ABS: subjects with lateral incisor absent (agenesis) in the cleft area.

RESULTS

The null hypothesis was rejected. Among UCLP subjects, there was a twofold increase (P < .0008) in overall frequency of tooth agenesis outside the cleft region in a subsample with cleft-side MxI2 agenesis (ABS), compared to a subsample presenting with no agenesis of the cleft-side MxI2 (M+D+MD).

CONCLUSIONS

Cleft-side MxI2 agenesis in CLP subjects appears to be largely a genetically controlled anomaly associated with cleft development, rather than a collateral environmental consequence of the adjacent cleft defect, since increased hypodontia involving multiple missing teeth observed remote from a cleft clearly has a significant genetic basis.

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.

Further evidence of association of the ABCA4 gene with cleft lip/palate

Non-syndromic cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex etiology. Numerous genes and environmental factors, and their interactions, are thought to play a role in the susceptibility to CL/P. A recent genome-wide association study with several populations revealed markers in/near transcription factor vmaf musculoaponeurtoic fibrosarcoma oncogene homolog B (MAFB) and ATP-binding cassette sub-family A member 4 (ABCA4) genes as new susceptibility loci for CL/P. We hypothesized that these genes could also contribute to CL/P in a Brazilian population, and hence we evaluated if the associated single-nucleotide polymorphisms (SNPs) in MAFB (rs13041247 and rs11696257) and ABCA4 (rs560426 and rs481931) were associated with CL/P in our case-control data set. We genotyped 812 Caucasian individuals (400 cases and 412 controls) from Brazil. Allele frequencies were compared for cases and controls as well as for cleft subgroups and controls. ABCA4 rs540426 showed strong associations with CL/P, unilateral and right CL/P, and bilateral CL/P, whereas the SNP rs481931 showed borderline associations with CL/P and bilateral CL/P . No association was found for MAFB. Our results support a potential role for ABCA4 in the etiology of CL/P in individuals from Brazil.

Dermatoglyphic Features in Nonsyndromic Cleft Lip and/or Palate Patients and Their Parents in China

OBJECTIVE

To test the hypothesis that indicators and fluctuating asymmetry (FA) on fingers and palms in nonsyndromic cleft lip and/or palate (NSCL/P) and their parents were affected by developmental instability and to investigate a potential way for prenatal diagnosis of NSCL/P.

DESIGN

Case-control study.

SETTING

West China College of Stomatology and Chengdu Children's Hospital, Chengdu, China.

PARTICIPANTS

Three hundred sixty NSCL/P patients and their 720 unaffected parents were collected. Two hundred ninety normal children and their 580 parents were selected as the control.

MAIN OUTCOME MEASURES

Total ridge counts, atd angle, fingerprints pattern types, a-b ridge count, and true pattern (TP) on palm were determined. For each indicator, asymmetry between hands was defined. Pattern types and asymmetries were statistically compared among groups.

RESULT

Compared with the control, NSCL/P patients had significantly greater a-b ridge count for both hands (P < .001), decreased TP in the left thenar area (TA) as well as in the hypothenar area (HA) and interdigital third area (I3) (all P < .05), and increased FA in HA and I3 (both P < .05), while their parents had greater a-b ridge counts (P < .001). NSCL/P patients possessed more slowly developing patterns and higher levels of FA on their palms, followed by their parents and then the controls.

CONCLUSION

A-b ridge count could be a potential prenatal indicator in people without family history that are at increased risk of having a child with NSCL/P. The increased tendency for slower development of patterns and higher levels of FA indirectly support the possibility that the developmental sequence of ridges in NSCL/P is retarded. However, further work is still needed.

[Facial coloboma: report of an exceptional prenatal case and interest of three-dimensional ultrasonography]

We report a rare case of Tessier no. 4 craniofacial cleft diagnosed by ultrasound imaging at 10 weeks' gestation. Tessier no. 4 craniofacial cleft is a very rare and complex congenital abnormality, characterized by an oblique orbitomaxillary facial cleft. Prenatal diagnosis of orofacial clefting is usually done at midtrimester of pregnancy, based on careful sonographic examination of the fetal face. However conventional 2D ultrasound is limited in screening isolated cleft palate and defects of the secondary palate. Thus, 3D ultrasound shows a greater sensitivity in a referred population and antenatal evaluation of facial clefs.

The evolution of human genetic studies of cleft lip and cleft palate

Orofacial clefts (OFCs)--primarily cleft lip and cleft palate--are among the most common birth defects in all populations worldwide, and have notable population, ethnicity, and gender differences in birth prevalence. Interest in these birth defects goes back centuries, as does formal scientific interest; scientists often used OFCs as examples or evidence during paradigm shifts in human genetics, and have also used virtually every new method of human genetic analysis to deepen our understanding of OFC. This review traces the evolution of human genetic investigations of OFC, highlights the specific insights gained about OFC through the years, and culminates in a review of recent key OFC genetic findings resulting from the powerful tools of the genomics era. Notably, OFC represents a major success for genome-wide approaches, and the field is poised for further breakthroughs in the near future.

Application of the International Classification of Functioning, Disability, and Health–Children and Youth Version (ICF-CY) to Cleft Lip and Palate

Objective

In recent health policy discussions, the World Health Organization has urged member states to implement the International Classification of Functioning, Disability, and Health: Children and Youth Version in their clinical practice and research. The purpose of this study was to identify codes from the International Classification of Functioning, Disability, and Health: Children and Youth Version relevant for use among children with cleft lip and/or palate, thereby highlighting the potential value of these codes for interprofessional cleft palate-craniofacial teams.

Design

The scope of recent published research in the area of cleft lip and/or palate was reviewed and compared with meaningful terms identified from the International Classification of Functioning, Disability, and Health: Children and Youth Version. In a five-step procedure, a consensus-based list of terms was developed that was linked separately to International Classification of Functioning, Disability, and Health: Children and Youth Version categories and codes. This provided a first draft of a core set for use in the cleft lip and/or palate field.

Conclusions

Adopting International Classification of Functioning, Disability, and Health: Children and Youth Version domains in cleft lip and/or palate may aid experts in identifying appropriate starting points for assessment, counseling, and therapy. When used as a clinical tool, it encourages health care professionals to go beyond treatment and outcome perspectives that are focused solely on the child and to include the children's environment and their familial/societal context. In order to establish improved, evidence-based interdisciplinary treatments for children with cleft lip and/or palate, more studies are needed that seek to identify all the influencing conditions of activities, children's participation, and barriers/facilitators in their environments.