Development Of Orofacial Clefts Research Articles

The presence and distribution of various genes in postnatal CLP-affected palatine tissue

BackgroundWorldwide cleft lip with or without a cleft palate (CL/P) is the most common craniofacial birth defect. Apart from changes in facial appearance, additionally affected individuals often suffer from various associated comorbidities requiring complex multidisciplinary treatment with overall high expenses. Understanding the complete pathogenetic mechanisms of CL/P might aid in developing new preventative strategies and therapeutic approaches, help with genetic counselling, and improve quality of life. Many genes have been associated with the development of orofacial clefts; however, the majority require further research. Based on the role of PAX7, PAX9, SHH, SOX3, WNT3A, and WNT9B in orofacial development, the intention was to use chromogenic in situ hybridization to detect the six genes in postnatal CLP-affected palatine tissue and compare their distribution within the tissue samples.ResultsStatistically significant differences in the distribution of PAX7, PAX9, WNT3A, and WNT9B were observed. In total, 19 pairs of moderate to very strong positive correlations were noted.ConclusionsChanges in the cleft-affected palatine epithelium primarily seem to be associated with the PAX7 gene; however, PAX9, WNT3A, WNT9B, and SOX3 role seems to be more limited. Whilst connective tissue changes seem to depend on PAX7 only, SHH seems to participate individually and indistinctly. Numerous positive correlations reflect the complicating interactions of the pathways and their components in the orofacial cleft morphopathogenesis.

MSX1 Gene Polymorphisms in Patients with non-Syndromic Cleft lip and Palate: A Tertiary Care Centre Based Case-Control Study from Central Kerala

Objective The purpose of this study was to investigate the contribution of MSX1 gene polymorphisms to the risk of developing NSCLP. Design Case-Control Study. Setting A tertiary care centre. Patients/Participants The sample consisted of 200 subjects (100 cases and 100 controls). Interventions None. Main Outcome Measure(s) Genotyping was performed by restriction fragment length polymorphism. Allele and genotype frequencies were calculated between patients and controls and analyzed using online Web Tools such as SISA and SNPstats. The MSX1 gene polymorphisms c. 799 GT, c.458 CA can be risk factors in the development of orofacial clefts. Results In the cases, an association was found between NSCLP and c.799 and c.458 of the MSX1 gene when compared with the control. The dominant and overdominant models, c. 799 GT, c.458 CA genotypes and c. 799 T, c.458 A alleles in the population are said to be the main risk factors to develop the NSCLP in our study population. The genotype variation of c 799 G/T and c.458 C/A are revealed to be specifically contributing to an NSCLP-type Cleft lip and Palate. It is worth noting that NSCLP females in the study population showed a stronger association with heterozygous genotypes of c.799 and c.458. However, further investigation with a larger cohort is necessary to confirm these findings. Conclusion Overall the results of the study revealed that MSX1 c 799 G > T and c.458 C > A can be considered as one of the genetic risk factors in the formation of Non-Syndromic Cleft Lip and Palate in the study population.

Alterations in DNA Methylation in Orofacial Clefts.

Orofacial clefts are among the most common craniofacial anomalies with multifactorial etiologies, including genetics and environments. DNA methylation, one of the most acknowledged mechanisms of epigenetics, is involved in the development of orofacial clefts. DNA methylation has been examined in patients with non-syndromic cleft lip with cleft palate (nsCL/P) from multiple specimens, including blood, saliva, lip, and palate, as well as experimental studies in mice. The results can be reported in two different trends: hypomethylation and hypermethylation. Both hypomethylation and hypermethylation can potentially increase the risk of nsCL/P depending on the types of specimens and the specific regions on each gene and chromosome. This is the most up-to-date review, intending to summarize evidence of the alterations of DNA methylation in association with the occurrence of orofacial clefts. To make things straightforward to understand, we have systematically categorized the data into four main groups: human blood, human tissues, animal models, and the factors associated with DNA methylation. With this review, we are moving closer to the core of DNA methylation associated with nsCL/P development; we hope this is the initial step to find a genetic tool for early detection and prevention of the occurrence of nsCL/P.

Patterns of orofacial clefts and associated risk factors in Pakistan

Background: Orofacial clefts (OFCs) are one of the most common congenital anomalies worldwide. The purpose of the present study is to identify the incidence of different types of OFCs and the presence of known risk factors among cleft cases in the Pakistani population. Patients and Methods: A retrospective study was conducted at a comprehensive cleft care center, and data were collected from patient files from December 2018 to July 2021. Only cases of cleft lip and/or cleft palate (CL/P) that presented to center were included. SPSS was used for data analysis, and risk factors associated with OFCs were identified. Results: The study included 1269 patients with CL/P. Of the total, 677 (53.3%) patients had cleft lip with cleft palate, 211 (16.6%) had cleft lip only, and 365 (28.7%) had cleft palate only. Bilateral complete cleft lip and palate (n = 276) was most common among the participants followed by midline incomplete cleft palate (n = 215). One hundred and six (8.3%) of the cases were syndromic, and among the remaining nonsyndromic cases, 240 (18.9%) had other associated anomalies. Chi-square tests revealed the following risk factors for CL/P: consanguinity among the parents (P < 0.001), a complication during pregnancy (P < 0.001), medication use during pregnancy (P < 0.001), maternal smoking or exposure to smoking (P = 0.002), history of miscarriage (P = 0.02), and positive family history (P < 0.001). Logistic regression analysis for these factors showed maternal smoking (odds ratio [OR]: 1.99), consanguineous marriage (OR: 1.89), complication during pregnancy (OR: 1.98), and positive history of cleft (OR: 1.9) to be increasing the odds of cleft development. Conclusion: While previous studies have shown many environmental factors to be associated with development of OFCs in the child, the present study provides a quantitative estimate of the risk posed by each individual factor in the Pakistani population.

Impact of Parental Consanguinity on the Frequency of Orofacial Clefts in Jordan.

Orofacial clefts (OFCs) are the most common craniofacial congenital anomalies, and its prevalence is highest among Asian populations. The aim of this retrospective case-control study is to evaluate the effect of parental consanguinity on the frequency of OFCs at Jordan University Hospital over a 15-year-period. The study group consists of all patients with OFCs presented to the major tertiary referral center in Jordan during the last 15 years, along with age and gender-matched controls. The authors analyzed the risk of different predictors, including consanguinity, on the development of OFCs, both cleft lip with or without cleft palate (CL/P) and cleft palate only. A total of 332 participants were included in this study, with a mean age of 74.36 (±48.75) months. The authors included 129 (38.9%) OFCs, and 203 (61.1%) controls. The percentage of parental consanguinity among OFCs group was 41.1%, compared to only 24.1% for controls, a difference that was statistically significant (P = 0.001). On logistic regression analysis, the authors found that parental consanguinity is a significant predictor for the occurrence of OFCs (P = 0.007), where people with consanguineous marriage have 2 times higher risk (odds ratio of 0.504, with 95% confidence interval 0.306-0.830) to have offspring with OFCs. Moreover, lower birth weight babies are also significantly more associated with OFCs (P = 0.014), with an odds ratio of 1.819 (95% confidence interval 1.131 2.926). Among the Jordanian population, the authors found that consanguinity and lower birth weight were the only variables significantly associated with the development of OFCs.

First trimester exposure to ambient gaseous air pollutants and risk of orofacial clefts: a case\u2013control study in Changsha, China

BackgroundA growing body of studies have investigated the association between air pollution exposure during early pregnancy and the risk of orofacial clefts, but these studies put more emphasis on particulate matter and reported inconsistent results, while research on the independent effects of gaseous air pollutants on orofacial clefts has been quite inadequate, especially in China.MethodsA case–control study was conducted in Changsha, China from 2015 to 2018. A total of 446 cases and 4460 controls were included in the study. Daily concentrations of CO, NO2, SO2, O3, PM2.5 and PM10 during the first trimester of pregnancy were assigned to each subject using the nearest monitoring station method. Multivariate logistic regression models were applied to evaluate the associations of monthly average exposure to gaseous air pollutants with orofacial clefts and its subtypes before and after adjusting for particulate matter. Variance inflation factors (VIFs) were used to determine if the effects of gaseous air pollutants could be independent of particulate matter.ResultsIncrease in CO, NO2 and SO2 significantly increased the risk of cleft lip with or without cleft palate (CL/P) in all months during the first trimester of pregnancy, with aORs ranging from 1.39 to 1.48, from 1.35 to 1.61 and from 1.22 to 1.35, respectively. The risk of cleft palate only (CPO) increased with increasing NO2 exposure levels in the first trimester of pregnancy, with aORs ranging from 1.60 to 1.66. These effects sustained and even exacerbated after adjusting for particulate matter. No significant effect of O3 was observed.ConclusionsOur study suggested that maternal exposure to CO, NO2, and SO2 during the first trimester of pregnancy might contribute to the development of orofacial clefts, and the associations were potentially independent of particulate matter.

Rare earth elements in umbilical cord and risk for orofacial clefts

Questions remain about the effects of rare earth elements (REEs) on reproductive health, and no study has explored in utero exposure to REEs and risk of orofacial clefts (OFCs). We recruited subjects from a case-control study conducted in Shanxi Province, China. Concentrations of fifteen REEs were quantified in umbilical cord samples by means of Inductively Coupled Plasma Mass Spectrometry measurements. We employed logistic regression and weighted quantile sum (WQS) regression models to estimate the association between REEs exposures and OFCs. Of 226 subjects included in our study, 34 were cleft lip only, 44 were cleft lip with cleft palate and 6 were cleft palate only. In the logistic regression model, concentrations above the median of all subjects were associated with an increased OFCs risk of 2.35-fold (95% CI: 1.22, 4.53) for Lanthanum and 2.12-fold for Neodymium (95% CI: 1.10, 4.10) adjusting for maternal age, BMI, gestational weeks, sex of infants and passive smoking. In WQS model, a quartile increase in the index resulting in an increase of 3.10 (95% CI: 1.38, 6.96) in the odds of OFC. Lanthanum and Neodymium were suggested to be important factors. The results were largely consistent for OFC subtypes. In conclusion, in utero exposure to mixtures of REEs increased the risk of OFCs. Lanthanum and Neodymium were likely to be important factors in the development of OFCs.

Selected essential trace elements in maternal serum and risk for fetal orofacial clefts

BackgroundDisturbances in the homeostasis of essential trace elements (ETEs) may interfere with embryonic organogenesis. However, the effect of ETEs on the development of orofacial clefts (OFCs) remains unclear. ObjectivesThis study examined associations between concentrations of iron (Fe), zinc (Zn), selenium (Se), cuprum (Cu), cobalt (Co), and molybdenum (Mo) in maternal serum and risk for OFCs in offspring. MethodsA total of 130 cases of OFCs and 260 nonmalformed controls were included in this study. Concentrations of Fe, Zn, Se, Cu, Co, and Mo in maternal serum were detected by inductively coupled plasma mass spectrometry. We examined associations between levels of the six ETEs in maternal serum and risk for OFCs for each element separately using multilevel mixed-effects logistic regression and for all elements collectively using Bayesian kernel machine regression (BKMR). ResultsHigher concentrations of Mo and Co in maternal serum were associated with a decreased risk for OFCs in a dose-dependent manner, with odds ratios and 95% confidence intervals of 0.37 (0.20–0.66) for the second tertile of Mo, 0.28 (0.15–0.54) for the third tertile of Mo, 0.54 (0.29–1.00) for the second tertile of Co, and 0.47 (0.25–0.87) for the third tertile of Co, with the lowest tertile as the referent. When all six ETEs were considered together, increased levels of ETEs were associated with a decreased risk for OFCs. In addition, Mo showed a protective effect against risk for OFCs when the other ETEs were fixed at their 25th, 50th, or 75th percentile, whereas the protective effect of Co turned to a null effect in the BKMR model. No association was observed between levels of Fe, Zn, Se, or Cu and risk for OFCs in either statistical model. ConclusionElevated concentrations of Mo in maternal serum were associated with a reduced risk for OFCs.

Protective effect of folic acid on vulnerability to oxidative stress in dental pulp stem cells of deciduous teeth from children with orofacial clefts

Orofacial clefts (OFCs) are among the most common congenital craniofacial malformations, including cleft lip with or without cleft palate as the core symptoms. Developmental or functional defects in neural crest cells (NCCs) that contribute to craniofacial morphogenesis are involved in OFC development. Previous studies have suggested that oxidative stress in NCCs is involved in the development of OFCs, suggesting that the anti-oxidative activity of folic acid (FA) could have protective effects. However, studies of human-derived NCCs are limited, as these cells are predominantly active during the embryonic stage. In this study, the effects of oxidative stress and FA were evaluated in human OFCs. In particular, NCC-derived stem cells from human exfoliated deciduous teeth (SHEDs) were obtained from 3 children with non-syndromic cleft lip with cleft palate (CLPs) and from 3 healthy children (CTRLs). Mitochondrial reactive oxygen species (ROS) levels were significantly higher in CLPs than in CTRLs and were associated with lower mRNA expression levels of superoxide dismutase 1 (SOD1) and decreased cell mobility. In addition, significantly greater vulnerability to pyocyanin-induced ROS, mimicking exogenous ROS, was observed in CLPs than in CTRLs. These vulnerabilities to endogenous and exogenous ROS in CLPs were significantly improved by FA. These results indicated that the transcriptional dysregulation of SOD1 in NCCs is an oxidative stress-related pathological factor in OFCs, providing novel evidence for the benefits of perinatal anti-oxidant supplementation, including FA, for the management of these common deformities.

Maternal Tobacco Exposure and Development of Orofacial Clefts in the Child: A Case-Control Study Conducted in Pakistan.

The purpose of this study was to evaluate the association between maternal tobacco exposure and development of orofacial clefts (OFCs) in the child in a Pakistani population. A case-control study was conducted at the Cleft Hospital and Bashir Hospital in Gujrat, Pakistan, from December 2015 to December 2016. All new cases of OFC at the Cleft Hospital were included. Patients at Bashir Hospital younger than 3 years and without congenital malformations were selected as control subjects. Risk factors associated with OFC were identified through bivariate analyses. Multiple logistic regression was then performed to calculate adjusted odds ratios (ORs) of developing OFC according to various risk factors. The study included 297 patients with OFC and 131 control subjects. Upon univariable analysis, the following were associated with OFC: maternal tobacco exposure (P < 0.001), complications during pregnancy (P < 0.001), maternal hypertension (P = 0.01), mother not on physician-recommended medications (P < 0.001), mother not receiving vaccinations (P < 0.001), consanguineous marriage (P < 0.001), and lower socioeconomic status (P < 0.001). Upon multivariable analysis, having a smoking parent (OR, 1.89; 95% confidence interval [CI], 1.10-3.26), complications during pregnancy (OR, 2.36; 95% CI, 1.43-3.88), and consanguineous marriage (OR, 1.79; 95% CI, 1.13-2.85) were associated with increased odds of development of OFC; receiving vaccinations (OR, 0.31; 95% CI, 0.16-0.63) and higher socioeconomic status (OR, 0.20; 95% CI, 0.05-0.74) were protective. Patients with OFC were nearly twice as likely to have a parent who smokes as those without. Efforts to reduce tobacco consumption among prospective parents, such as perinatal tobacco cessation counseling programs, should be evaluated in this population.

Risk factors and comorbidities in Brazilian patients with orofacial clefts.

Considering that environmental risk factors substantially contribute to the etiology of orofacial clefts and that knowledge about the characteristics and comorbidities associated with oral clefts is fundamental to promoting better quality of life, this study aimed to describe the risk factors, main characteristics, and comorbidities of a group of patients with cleft lip and/or cleft palate (CL/P) from Rio Grande do Norte (RN), Brazil. Data were obtained from 173 patients with CL/P using a form from the Brazilian database on Orofacial Clefts. Most patients were male with cleft lip and palate and had a normal size and weight at birth; presented few neonatal intercurrent events; and had anemia and respiratory and cardiovascular diseases as main associated comorbidities. They also required timely surgical rehabilitation and multidisciplinary care to stimulate their neuropsychomotor development. In addition, a high frequency of familial recurrence and of parental consanguinity was evidenced in the studied population, especially for the cleft lip and cleft palate type. Other relevant findings were the considerable maternal exposure to alcohol, infections, smoking, and hypertension, as well as low supplementation with vitamins and minerals and deliberate consumption of analgesics, antibiotics, and antihypertensives during pregnancy. Characterization of the CL/P patient profile is essential for the planning of health services and integration among the health professionals involved in the diagnosis and treatment of these malformations. Our results reinforce the need for additional research to confirm the association between environmental factors and the development of orofacial clefts.

Abstract: Maternal Tobacco Exposure and Risk of Orofacial Clefts in the Child

INTRODUCTION: While a relationship between maternal tobacco exposure and development of orofacial clefts in the child has been established for some time, the actual degree of risk conferred is not well quantified.1–3 A better understanding of this risk would benefit prenatal specialists in the counseling of prospective parents.4 The purpose of this study was to quantify the risk for cleft lip and/or cleft palate (CLP) associated with maternal tobacco exposure. METHODS: A case-control study was conducted at the Cleft Hospital and the Bashir Hospital in Gujrat, Pakistan from December 2015 to December 2016. All new cases of CLP at the Cleft Hospital were included in the study. Infants and children of three years of age or less at the Bashir Hospital were concurrently chosen to serve as control cases if they had no congenital malformations, were born or living in the same area as the patients in the study with CLP, and were of comparable socioeconomic standing to those patients. Bivariate analyses were performed to identify risk factors associated with CLP. These variables were then included alongside maternal tobacco exposure (whether one or both parents smoke) in a multiple logistic regression to calculate the adjusted odds ratio of developing CLP associated with tobacco exposure. RESULTS: A total of 329 patients with CLP and 131 controls were included in the study. Upon bivariate analysis, the following factors were associated with CLP: maternal tobacco exposure (p<0.001), complications during pregnancy (p<0.001), maternal hypertension (p=0.01), mother not on any medications (p<0.001), mother not receiving vaccinations (p<0.001), and lower socioeconomic status (p<0.001). After adjustment for these variables, having a smoking parent was associated with a 2.09 times increased odds of the child developing CLP (95% CI 1.22–3.58). Complications during pregnancy (OR=2.38, 95% CI 1.45–3.90), mother receiving vaccinations (OR = 0.32, 95% CI 0.16–0.64), and higher socioeconomic status (OR = 0.15, 95% CI 0.04–0.63) were also associated with CLP. CONCLUSION: While previous studies have consistently shown maternal tobacco exposure to be associated with development of orofacial clefts in the child, this study identifies and accounts for possible confounding variables in a case-control design, thereby providing a quantified estimate of the risk conferred by maternal tobacco exposure. This finding will be of value to providers in the context of perinatal counseling. Reference Citations: 1. Wyszynski DF, Duffy DL, Beaty TH. Maternal Cigarette Smoking and Oral Clefts: A Meta-analysis. Cleft Palate-Craniofacial J. 1997;34(3):206–210. doi:10.1597/1545–1569(1997)034<0206:MCSAOC>2.3.CO;2. 2. Little J, Cardy A, Munger RG. Tobacco smoking and oral clefts: a meta-analysis. Bull World Health Organ. 2004;82(3):213–218. 3. Xuan Z, Zhongpeng Y, Yanjun G, et al. Maternal active smoking and risk of oral clefts: a meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol. 2016;122(6):680–690. doi:10.1016/j.oooo.2016.08.007. 4. Elahi MM, Jackson IT, Elahi O, et al. Epidemiology of cleft lip and cleft palate in Pakistan. Plast Reconstr Surg. 2004;113(6):1548–1555. doi:10.1097/01.PRS.0000117184.77459.2B.

Distinct DNA methylation profiles in subtypes of orofacial cleft

BackgroundEpigenetic data could help identify risk factors for orofacial clefts, either by revealing a causal role for epigenetic mechanisms in causing clefts or by capturing information about causal genetic or environmental factors. Given the evidence that different subtypes of orofacial cleft have distinct aetiologies, we explored whether children with different cleft subtypes showed distinct epigenetic profiles.MethodsIn whole-blood samples from 150 children from the Cleft Collective cohort study, we measured DNA methylation at over 450,000 sites on the genome. We then carried out epigenome-wide association studies (EWAS) to test the association between methylation at each site and cleft subtype (cleft lip only (CLO) n = 50; cleft palate only (CPO) n = 50; cleft lip and palate (CLP) n = 50). We also compared methylation in the blood to methylation in the lip or palate tissue using genome-wide data from the same 150 children and conducted an EWAS of CLO compared to CLP in lip tissue.ResultsWe found four genomic regions in blood differentially methylated in CLO compared to CLP, 17 in CPO compared to CLP and 294 in CPO compared to CLO. Several regions mapped to genes that have previously been implicated in the development of orofacial clefts (for example, TBX1, COL11A2, HOXA2, PDGFRA), and over 250 associations were novel. Methylation in blood correlated with that in lip/palate at some regions. There were 14 regions differentially methylated in the lip tissue from children with CLO and CLP, with one region (near KIAA0415) showing up in both the blood and lip EWAS.ConclusionsOur finding of distinct methylation profiles in different orofacial cleft (OFC) subtypes represents a promising first step in exploring the potential role of epigenetic modifications in the aetiology of OFCs and/or as clinically useful biomarkers of OFC subtypes.

Usage of Potential Teratogenic Chemical Preparations among Mothers of Children Attending the Multidisciplinary Cleft Clinic at the Komfo Anokye Teaching Hospital, Ghana

Objective: The purpose of this study is to determine the usage of potential teratogenic chemicals among cleft lip and palate mothers attending a multidisciplinary cleft clinic at Komfo Anokye Teaching Hospital (KATH). Method: This is a retrospective study based on records of consecutive patients attending the multidisciplinary cleft clinic at KATH. Mothers of children with cleft lip and palate formed the study sample. Information on the use of chemical agents by the mothers either before or during the first three months of pregnancy was collected on to a specially designed form. The study period was from January 2006 to December 2012. Setting: The study was carried out in a multidisciplinary cleft clinic at Komfo Anokye Teaching Hospital in Ghana. The clinic is the main referral centre for the northern sector of Ghana for cleft lip and palate care. Results: Chemical preparations usage ranged from 0.2% for tobacco to 25.3% for skin lightening creams. Other agents used include, enema, non-proprietary concoctions and prednisolone tablets. 2.1% of the mothers ingested alcohol during pregnancy. Conclusion: There is a high level of usage of potentially teratogenic chemicals among cleft mothers attending the multidisciplinary cleft lip and palate clinic at the Komfo Anokye Teaching Hospital in Ghana. Further studies are, however, required to clarify any relationship this may have with the development of orofacial clefts.

Chromosomal Abnormalities in Finnish Orofacial Cleft Patients: Excess of Submucous Cleft Patients?

The aim was to identify chromosomal regions possibly involved in the development of orofacial clefts and to compare syndromic cleft phenotypes with previous reports. We have retrospectively gathered and analyzed chromosomal aberrations and phenotypes of Finnish cleft patients treated at the Cleft and Craniofacial Centre, Helsinki University Central Hospital. The study was carried out at the Cleft and Craniofacial Centre, Helsinki University Central Hospital. The cleft register contains information on about 7600 Finnish cleft patients. Identification of patients for further molecular analyses and identification of chromosomal regions associated with orofacial clefting. We identified 37 cleft patients with chromosomal aberrations of putative research interest. We were able to efficiently select patients for further molecular analyses and identify chromosomal regions that might be associated with orofacial clefting. The percentage of submucous cleft patients among cleft patients with chromosomal aberrations was unexpectedly high.

Length of the Cervical Spine As a Factor in the Etiology of Cleft Palate

The length of the cervical spine in a series of 206 adult males with cleft lip and/or palate and 50 normal controls was measured. The patients were divided into five subgroups according to the type and extent of the cleft. The shortening of the spine was most marked in bilateral cleft lip and palate patients (complete), less marked in unilateral cleft lip and palate patients, and was slight in isolated cleft palate patients. Complete isolated cleft palate and cleft lip was not associated with a shortening of the spine. A shortening of the cervical spine in less extensive types of isolated cleft palate was suggestive of the participation of the spine in their development, while in cleft lip and palate a simultaneous exposure to a teratogenic agent or any other developmental error during early stages of embryogenesis could explain the concomitant occurrence of spine anomalies. Patients with cleft lip and palate associated with a short spine also had a shorter mandibular ramus, which could be suggestive of simultaneous damage to both structures during morphogenesis. This relationship was not demonstrated in isolated cleft palate that developed in later stages of embryogenesis. In these cases a short spine itself could not have impaired the growth potential of the mandible, yet it could have mechanically induced the development of cleft palate. These observations are in agreement with the present state of knowledge on the development of orofacial clefts as shown in experimental animals.

Length of the Cervical Spine as a Factor in the Etiology of Cleft Palate

The length of the cervical spine in a series of 206 adult males with cleft lip and/or palate and 50 normal controls was measured. The patients were divided into five subgroups according to the type and extent of the cleft. The shortening of the spine was most marked in bilateral cleft lip and palate patients (complete), less marked in unilateral cleft lip and palate patients, and was slight in isolated cleft palate patients. Complete isolated cleft palate and cleft lip was not associated with a shortening of the spine. A shortening of the cervical spine in less extensive types of isolated cleft palate was suggestive of the participation of the spine in their development, while in cleft lip and palate a simultaneous exposure to a teratogenic agent or any other developmental error during early stages of embryogenesis could explain the concomitant occurrence of spine anomalies. Patients with cleft lip and palate associated with a short spine also had a shorter mandibular ramus, which could be suggestive of simultaneous damage to both structures during morphogenesis. This relationship was not demonstrated in isolated cleft palate that developed in later stages of embryogenesis. In these cases a short spine itself could not have impaired the growth potential of the mandible, yet it could have mechanically induced the development of cleft palate. These observations are in agreement with the present state of knowledge on the development of orofacial clefts as shown in experimental animals.

Confirmation of an association between RFLPs at the transforming growth factor-alpha locus and non-syndromic cleft lip and palate.

Three RFLPs at the TGFA locus were studied in 60 unrelated British Caucasian subjects with non-syndromic cleft lip/palate and 60 controls. A highly significant association between the TaqI RFLP and the occurrence of clefting was found (chi 2 = 15.04, p = less than 0.001). No significant association was found with the two other RFLPs studied (BamHI and RsaI). Haplotypes derived from the three RFLPs at the TGFA locus also showed an over-representation of the C2A2B2 haplotype in cases compared to controls. Analyses of genotypes according to type of cleft and the presence or absence of a family history of clefting were also carried out. These results provide further support for the role of TGFA as a gene of major effect in the development of orofacial clefts in humans.