Subphenotyping and Classification of Orofacial Clefts: Need for Orofacial Cleft Subphenotyping Calls for Revised Classification

Association of Perioperative Antibiotics with the Prevention of Postoperative Fistula after Cleft Palate Repair

Background

There is debate amongst surgeons regarding the use of antibiotics to prevent fistulae after palatoplasty. Prescribing should be evidence based, as antibiotic stewardship is integral to reducing antibiotic resistance. Our aim was to determine whether differing perioperative regimens affect the prevalence of postoperative fistulae.

Methods

The sample comprised participants from the Cleft Collective who had undergone palatoplasty. Participants were recruited across all 16 UK cleft centers between 2013 and 2021. The exposure was perioperative antibiotic regimen prescribed at the time of palatoplasty. The primary outcome was the presence of palatal fistula.

Results

Fistula data were available for 167 participants when exploring antibiotic regimen and for 159 when exploring antibiotic agent. There was no evidence to suggest a difference in fistula rate between those receiving antibiotics on induction only versus as an inpatient or up to 7 days postoperatively (χ2 = 4.57; P = 0.10). There was no evidence to suggest a difference in fistula rate between those who received co-amoxiclav and those who had an alternative antibiotic (χ2 = 0.16; P = 0.69). Postoperative fistulae increased with the extent of the cleft (χ2 = 20.39; P < 0.001). When adjusting for cleft type, no evidence of an association between antibiotic regimen and fistulae was found (inpatient antibiotics: OR 1.36; 95% confidence interval, 0.53-3.51; antibiotics up to 7 days postoperatively: OR 0.68; 95% confidence interval, 0.26-1.80).

Conclusions

The choice of antibiotic and dosing regimen does not influence the formation of postoperative fistulae. These results should be supported by interventional trials.

Harnessing the Power of Artificial Intelligence in Cleft Lip and Palate: An In-Depth Analysis from Diagnosis to Treatment, a Comprehensive Review

Cleft lip and palate (CLP) is the most common craniofacial malformation, with a range of physical, psychological, and aesthetic consequences. In this comprehensive review, our main objective is to thoroughly examine the relationship between CLP anomalies and the use of artificial intelligence (AI) in children. Additionally, we aim to explore how the integration of AI technology can bring about significant advancements in the fields of diagnosis, treatment methods, and predictive outcomes. By analyzing the existing evidence, we will highlight state-of-the-art algorithms and predictive AI models that play a crucial role in achieving precise diagnosis, susceptibility assessment, and treatment planning for children with CLP anomalies. Our focus will specifically be on the efficacy of alveolar bone graft and orthodontic interventions. The findings of this review showed that deep learning (DL) models revolutionize the diagnostic process, predict susceptibility to CLP, and enhance alveolar bone grafts and orthodontic treatment. DL models surpass human capabilities in terms of precision, and AI algorithms applied to large datasets can uncover the intricate genetic and environmental factors contributing to CLP. Additionally, Machine learning aids in preoperative planning for alveolar bone grafts and provides personalized treatment plans in orthodontic treatment. In conclusion, these advancements inspire optimism for a future where AI seamlessly integrates with CLP management, augmenting its analytical capabilities.

Maternal Exposure to Stress During Covid-19 and Non-Syndromic Orofacial Clefts: A Cohort Retrospective Study

OBJECTIVE

The coronavirus (COVID-19) pandemic presents an opportunity to study stress's effect on the development of non-syndromic orofacial clefts (NSOFCs). This study was aimed at assessing maternal stress exposure during the pregestational to first trimester pregnancy periods and the development of NSOFCs during a year of the COVID-19 pandemic.

DESIGN

Cohort study of infants with NSOFCs and controls matched based on recruitment site and age.

SETTING

Government hospitals in Saudi Arabia between November 2020 and November 2021.

MAIN OUTCOME MEASURES

Data collection included NSOFC clinical examination and maternal stress exposure assessment using the Modified Life Events Questionnaire, the Fear of COVID-19 Scale, and a focus on the lack of pregnancy planning and a threatened miscarriage.

RESULTS

Of the 557 infants recruited, 191 had NSOFCs. Logistic regression analysis with adjusted odds ratios (AORs) that removed the effects of confounders showed that any of the seven stressful life events (AOR:3.78, P < .001) and the family histories of relatives with NSOFCs (AOR:9.73, P < .001) increased the AOR for NSOFC development. In contrast, maternal folic acid (AOR:0.56, P.010), threatened miscarriage (AOR:0.17, P = .001), fear of COVID-19 (AOR:0.83, P = .038), and suspected COVID-19 infection (AOR:0.43, P = .008) decreased the AOR for NSOFC development.

CONCLUSION

Along with an established risk associated with family history of birth defects, stressful life events may be a risk factor for NSOFC development. Beyond folic acid's known benefit, it may be that higher maternal health concerns contribute to increased protective health behaviors during pregnancy. Ongoing research is needed to specify the maternal risk factors for NSOFC.

Classification Systems of Cleft Lip, Alveolus and Palate: Results of an International Survey

OBJECTIVE

This study aimed to identify commonly used classification systems by cleft providers around the world, including the perceived indications and limitations of each system.

DESIGN

A cross-sectional survey.

PARTICIPANTS

A total of 197 registrants from three international cleft/craniofacial meetings.

INTERVENTIONS

Participants were sent a web-based questionnaire concerning cleft classification systems.

MAIN OUTCOME MEASURES

Frequency of commonly used classification systems, their perceived indications and limitations.

RESULTS

A total of 197 respondents from 166 different centers completed the questionnaire. Healthcare professionals from all disciplines responded, with the most frequent respondents being plastic surgeons (38.1%), maxillofacial surgeons (28.4%) and orthodontists (23.9%). Eighteen different classification systems were in use. The most frequently used systems were the International Statistical Classification of Diseases and Related Health Problems (ICD-10) (35.5%), LAHSHAL (34.0%), and Veau (32.5%) classification systems. Most respondents (32.5%) indicated that anatomical and morphological characteristics are essential components of a classification system. However, respondents indicated that their current classification systems lacked sufficient description of cleft extension and severity.

CONCLUSIONS

Great variety in the use of classification systems exists among craniofacial specialists internationally. The results recommend the usage of the LAHSHAL classification of OFCs, due to its comprehensiveness, relatively high implementation rate globally, convenience of usage and complementarity with the ICD-10 system. Moreover, it can overcome deficiencies inextricably linked to ICD-10, such as incapacity to describe laterality and clefts of the alveolus. More international exposure to the merits of using the LAHSHAL classification system would be highly recommended.

Dentition patterns in bilateral cleft lip subphenotypes: multicenter study

OBJECTIVES

Here, we retrospectively investigated cases of bilateral oral clefts (OCs) to determine the clinical relevance of detailed distinction of incomplete cleft lip subphenotypes, based on morphological severity of the cleft, within the categories cleft lip with or without alveolus (CL ± A) and cleft lip, alveolus, and palate (CLAP). We further assessed possible associations between CL subphenotypes (complete vs different incomplete types) and different dentition patterns of the lateral incisor.

MATERIALS AND METHODS

Our analysis included 151 non-syndromic Caucasian bilateral OC-patients (8-20 years old) from the Dutch Association for Cleft Palate and Craniofacial Anomalies registry. Six different deciduous and permanent lateral incisor patterns were distinguished: normal position (z/Z), supernumerary lateral incisor (n/N), presence in the anterior (x/X) or posterior (y/Y) segment of the cleft, one in each cleft segment (xy/XY), and agenesis (ab/AB). Logistic regression was performed to show the associations between the CL subphenotypes and dentition patterns of the lateral incisor.

RESULTS

One hundred three had complete, while 48 had incomplete CLs. Patterns z/Z and n/N were associated with a submucous/vermillion notch, incomplete CL, and intact alveolus. Patterns x/X, y/Y, and xy/XY were most common in patients with two-thirds to subtotal CL and complete CL. The most severe pattern, ab/AB, was most commonly associated with complete CL.

CONCLUSIONS

Based on the morphological severity of the CLs, it can be stated that the more severe the CL in bilateral CL ± A and CLAP, the more severe the abnormal pattern of the dentition.

CLINICAL RELEVANCE

Further distinction of incomplete cleft lip subphenotypes (submucous/vermillion notch, one-third to two-thirds CL, two-thirds to subtotal CL) in bilateral CL ± A and CLAP has clinical relevance.

Fetal markers for the detection of infants with craniofacial malformation

Facial clefts and Robin sequence (RS) share the timing of the diagnosis during the course of pregnancy, their association with genetic diseases and the subsequent management following the initial diagnosis. If a suspicion of a facial cleft or RS is made, a detailed anatomical examination of the fetus should be carried out to identify further anomalies. This may also involve genetic testing including a microarray or an exome analysis. Interdisciplinary counseling, including pre- and postnatal experts with sufficient experience in the management of such neonates, should be involved in this counseling. Parents should be informed about disease-specific therapeutic options and postnatal outcome. Delivery should take place in a center with experience in craniofacial malformations where clinicians are prepared for potentially life-threatening airway obstruction immediately after birth.

Exploring the Relationship Between Palatal Cleft Type and Width With the Use of Relieving Incisions in Primary Repair

OBJECTIVE

The mainstay of palatal repair in the United Kingdom is the intravelar veloplasty (IVVP). It is not always possible to align the oral mucosa in the midline to achieve tension-free repair. The addition of lateral relieving incisions may aid transposition of the oral mucosa to allow closure. The aim of this study was to explore cleft features that may predispose to a requirement for relieving incisions in order to allow palate closure.

DESIGN

We performed a national multiinstitutional retrospective study using data from the UK Cleft Collective cohort study.

PATIENTS

The study sample consisted of 474 patients who had undergone IVVP at the time of palatal closure across all 16 of the UK cleft units.

RESULTS

We found strong evidence for the requirement for relieving incisions in patients with an increased degree of clefting per the Veau classification (P < .001), increasing palatal soft-edge width (P < .001) and moderate evidence of an associated use in patients with Pierre Robin sequence (P = .015). Insufficient data were available to explore the relationship between intertuberosity distance and the presence of fistula formation with the use of relieving incisions.

CONCLUSIONS

The results of this study identify cleft features that increase the likelihood for requiring lateral relieving incisions to allow palatal closure. The degree to which the addition of relieving incisions to IVVP affects maxillary growth and speech outcomes is unknown. Further study is required to answer this important question.

Epidemiologic trends of infants with orofacial clefts in a multiethnic country: a retrospective population-based study

Cleft births surveillance is essential in healthcare and prevention planning. Data are needed in precision medicine to target upstream management for at-risk individuals. This study characterizes Singapore's population-based orofacial cleft topography by ethnicity and gender, and establishes the cleft cohort's infant mortality rate. Data, in the decade 2003 to 2012, were extracted by the National Birth Defects Registry. Trend testing by linear regression was at p < 0.05 significance level. Prevalence per 10,000 for population-based cleft live births was 16.72 with no significant upward trend (p = 0.317). Prevalence rates were 8.77 in the isolated cleft group, 7.04 in the non-isolated cleft group, and 0.91 in the syndromic cleft group. There was significant upward trend in infants with non-isolated clefts (p = 0.0287). There were no significant upward trends in infants with isolated clefts and syndromic clefts. Prevalence rates were sexually dimorphic and ethnic-specific: male 17.72; female 15.78; Chinese group 17.17; Malay group 16.92; Indian group 10.74; and mixed ethnic origins group 21.73. The overall infant mortality rate (IMR) was 4.8% in the cohort of 608 cleft births, which was more than double the population-based IMR of 2.1% in the same period. Infants with non-isolated and syndromic clefts accounted for 96.6% of the deaths.

Orofacial clefts embryology, classification, epidemiology, and genetics

Orofacial clefts (OFCs) rank as the second most common congenital birth defect in the United States after Down syndrome and are the most common head and neck congenital malformations. They are classified as cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). OFCs have significant psychological and socio-economic impact on patients and their families and require a multidisciplinary approach for management and counseling. A complex interaction between genetic and environmental factors contributes to the incidence and clinical presentation of OFCs. In this comprehensive review, the embryology, classification, epidemiology and etiology of clefts are thoroughly discussed and a "state-of-the-art" snapshot of the recent advances in the genetics of OFCs is presented.

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.

Seasonal Influence on the Numbers of Gender-Related Orofacial Cleft Conceptions in the Netherlands

BACKGROUND

In the multifactorial etiology of orofacial clefts (OFCs), environmental factors play an important role. To trace the influence of these factors, the timing of the cell biological mechanisms that occur during embryological development of the primary and secondary palates must be taken into account. That is, the fusion process of the facial and palatal processes, respectively, followed by their differentiation into bone and musculature, which take place during the first trimester of pregnancy. During this period, harmful seasonal influences such as viral infections and vitamin deficiencies could induce OFC in the embryo.

AIMS

The aim of this study is to find out whether a seasonal conception period with an increased risk of OFC development exists, particularly gender related.

METHODS

This was a retrospective cross-sectional study on children with OFC born in the Netherlands from 2006 to 2016. Total conception rates of live births in the Netherlands were used as a control group. χ² tests were performed to analyze monthly and seasonal differences. Males and females, positive and negative family history and subphenotype groups based on fusion and/or differentiation (F- and/or D-) defects, and their timing in embryogenesis were analyzed separately.

RESULTS

In total, 1653 children with OFC, 1041 males and 612 females, were analyzed. Only males with FD-defects showed a significant seasonal variation with an increase in conceptions during spring, most often in May.

CONCLUSIONS

Males with FD-defects showed a significant seasonal variation with an increase in conceptions during spring. No other seasonal trends could be demonstrated.

Innovative Molecular and Cellular Therapeutics in Cleft Palate Tissue Engineering

Clefts of the lip and/or palate are the most prevalent orofacial birth defects occurring in about 1:700 live human births worldwide. Early postnatal surgical interventions are extensive and staged to bring about optimal growth and fusion of palatal shelves. Severe cleft defects pose a challenge to correct with surgery alone, resulting in complications and sequelae requiring life-long, multidisciplinary care. Advances made in materials science innovation, including scaffold-based delivery systems for precision tissue engineering, now offer new avenues for stimulating bone formation at the site of surgical correction for palatal clefts. In this study, we review the present scientific literature on key developmental events that can go awry in palate development and the common surgical practices and challenges faced in correcting cleft defects. How key osteoinductive pathways implicated in palatogenesis inform the design and optimization of constructs for cleft palate correction is discussed within the context of translation to humans. Finally, we highlight new osteogenic agents and innovative delivery systems with the potential to be adopted in engineering-based therapeutic approaches for the correction of palatal defects. Impact statement Tissue-engineered scaffolds supplemented with osteogenic growth factors have attractive, largely unexplored possibilities to modulate molecular signaling networks relevant to driving palatogenesis in the context of congenital anomalies (e.g., cleft palate). Constructs that address this need may obviate current use of autologous bone grafts, thereby avoiding donor-site morbidity and other regenerative challenges in patients afflicted with palatal clefts. Combinations of biomaterials and drug delivery of diverse regenerative cues and biologics are currently transforming strategies exploited by engineers, scientists, and clinicians for palatal cleft repair.

Pax9's dual roles in modulating Wnt signaling during murine palatogenesis

BACKGROUND

Despite the strides made in understanding the complex network of key regulatory genes and cellular processes that drive palate morphogenesis, patients suffering from these conditions face treatment options that are limited to complex surgeries and multidisciplinary care throughout life. Hence, a better understanding of how molecular interactions drive palatal growth and fusion is critical for the development of treatment and preventive strategies for cleft palates in humans. Our previous work demonstrated that Pax9-dependent Wnt signaling is critical for the growth and fusion of palatal shelves. We showed that controlled intravenous delivery of small molecule Wnt agonists specifically blocks the action of Dkks (inhibitors of Wnt signaling) and corrects secondary palatal clefts in Pax9^-/- mice. While these data underscore the importance of the functional upstream relationship of Pax9 to the Wnt pathway, not much is known about how the genetic nature of Pax9's interactions in vivo and how it modulates the actions of these downstream effectors during palate formation.

RESULTS

Here, we show that the genetic reduction of Dkk1 during palatogenesis corrected secondary palatal clefts in Pax9^-/- mice with restoration of Wnt signaling activities. In contrast, genetically induced overexpression of Dkk1 mice phenocopied the defects in tooth and palate development visible in Pax9^-/- strains. Results of ChIP-qPCR assays showed that Pax9 can bind to regions near the transcription start sites of Dkk1 and Dkk2 as well as the intergenic region of Wnt9b and Wnt3 ligands that are downregulated in Pax9^-/- palates.

CONCLUSIONS

Taken together, these data suggest that the molecular mechanisms underlying Pax9's role in modulating Wnt signaling activity likely involve the inhibition of Dkk expression and the control of Wnt ligands during palatogenesis.

Embryologically Based Classification Specifies Gender Differences in the Prevalence of Orofacial Cleft Subphenotypes

Background:

A recently published validated classification system divides all orofacial cleft (OFC) subphenotypes into groups based on underlying developmental mechanisms, that is, fusion and differentiation, and their timing, that is, early and late periods, in embryogenesis of the primary and secondary palates.

Aims:

The aim of our study was to define gender differences in prevalence for all subphenotypes in newborns with OFC in the Netherlands.

Methods:

This was a retrospective cross-sectional study on children with OFC born from 2006 to 2016. Clefts were classified in early (E-), late (L-), and early/late (EL-) embryonic periods, in primary (P-), secondary (S-), and primary/secondary (PS-) palates, and further divided into fusion (F-), differentiation (D-), and fusion/differentiation (FD-) defects, respectively.

Results:

A total of 2089 OFC children were analyzed (1311 males and 778 females). Orofacial cleft subphenotypes in females occurred significantly more frequent in the L-period compared to males (66% vs 55%, P = .000), whereas clefts in males occurred significantly more in the EL-periods (40% vs 27%, P = .000). Females had significantly more S-palatal clefts (42% vs 23%, P = .000), while males had significantly more PS-palatal clefts (44% vs 30%, P = .000). Furthermore, the clefts in females were significantly more frequent the result of an F-defect (60% vs 52%, P = .000).

Conclusions:

Orofacial cleft in females mainly occur in the L-period are mostly S-palatal clefts, and are usually the result of an F-defect. Orofacial cleft in males more commonly occur in the EL-periods, are therefore more often combined PS-palatal clefts, and are more frequent D- and FD-defects.

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.

Subphenotyping and Classification of Cleft Lip and Alveolus in Adult Unoperated Patients: A New Embryological Approach

OBJECTIVE

Previously, a new embryological classification was introduced subdividing oral clefts into fusion and/or differentiation defects. This subdivision was used to classify all subphenotypes of cleft lip with or without alveolus (CL±A). Subsequently, it was investigated whether further morphological grading of incomplete CLs is clinically relevant, and which alveolar part is deficient in fusion/differentiation defects.

DESIGN

Observational cohort study.

SETTING

Three hundred fifty adult unoperated Indonesian cleft patients presented themselves for operation. Cephalograms, dental casts, and intraoral and extraoral photographs-eligible for the present study-were used to determine morphological severity of CL±A.

PATIENTS

Patients with unilateral or bilateral clefts of the primary palate only were included.

MAIN OUTCOME MEASURES

Clefts were classified-according to developmental mechanisms and timing in embryogenesis-as fusion and/or differentiation defects. Grades of incomplete CLs were related to the severity of alveolar clefts (CAs) and hypoplasia, and permanent dentition was used to investigate which alveolar part is deficient in fusion/differentiation defects.

RESULTS

One hundred eight adult patients were included. All subphenotypes-96 unilateral and 12 bilateral clefts-could be classified into differentiation (79%), fusion (17%), fusion-differentiation (2%), or fusion and differentiation (2%) defects. The various grades of incomplete CLs were related to associated CAs and hypoplasia, and all alveolar deformities were located in the premaxillae.

CONCLUSIONS

This study showed that all CL±A including the Simonart bands can be classified, that further morphological grading of incomplete CLs is clinically relevant, and that the premaxilla forms the deficient part in alveolar deformities.

ICD-10 impact on ascertainment and accuracy of oral cleft cases as recorded by the Brazilian national live birth information system

We compared Brazilian oral cleft (OC) frequencies between the population-based Brazilian System of Live Birth (SINASC) and the hospital-based Latin American Collaborative Study of Congenital Malformations (ECLAMC), trying to understand the paucity of cleft of lip and palate (CLP) in the first system. SINASC uses the International Classification of Disease version 10 (ICD-10) for congenital defects coding, ECLAMC uses ICD-8 with modifications. In SINASC, the CLP frequency was 1.7 per 10,000 (95% confidence limits 1.7-1.8), cleft lip (CL) 1.6 (1.5-1.7), and cleft palate (CP) 2.0 (1.9-2.1). In ECLAMC, the CLP frequency was 10.4 per 10,000 (9.0-12.1), CL 5.5 (4.5-6.7), and CP 4.4. (4.5-6.7). In SINASC, only 33% of the oral clefts were CLP, versus 51% in ECLAMC. Part of this discrepancy may have been due to the relative excess of CP and CL cases. Although congenital defect frequencies are usually lower in population than in hospital-based registries, differences in the proportion of the main OC categories are not expected and are probably due to ICD-10 coding issues, such as lumping of unilateral CL and CL without other specifications. ICD-10 codes, whose deficiency for oral clefts is fully explained in the literature, lack modifiers for severity, or clinical subtypes. This paper shows the practical aspect of the ICD-10 system deficiency in capturing cleft lip and palate (CLP) subtypes, as demonstrated in SINASC covering three million births per year. Such errors are expected to occur in any registry that uses the ICD-10 coding system, and must be adjusted, given its relevance worldwide.

Dentition Patterns in Different Unilateral Cleft Lip Subphenotypes

Oral clefts play an essential role in disturbed odontogenesis of the deciduous and permanent dentition, yet little is known about this relationship. We investigated, within the categories cleft lip with or without alveolus (CL ± A) and cleft lip, alveolus and palate (CLAP), whether different CL subphenotypes based on morphological severity of the cleft show different dentition patterns and whether a more detailed subdivision of the incomplete CL has clinical relevance. In this retrospective study, 345 children with nonsyndromic unilateral CL ± A and CLAP from the Dutch Association for Cleft Palate and Craniofacial Anomalies (NVSCA) registry were included to assess the association between the CL subphenotypes and lateral incisor patterns. Five different deciduous and permanent patterns of the lateral incisor were distinguished: located in normal position (pattern z/Z), in the anterior segment (pattern x/X) or in the posterior segment of the cleft (pattern y/Y), one in each segment of the cleft (pattern xy/XY), and agenesis of the lateral incisor (pattern ab/AB). Analyses were performed by using multinomial logistic regression models. Children born with a vermillion notch or a one-third to two-thirds CL were most likely to have a deciduous pattern x and a permanent pattern X, while children born with a two-thirds to subtotal CL were most likely to have deciduous pattern xy and a permanent pattern X compared to children with a complete CL that predominantly had deciduous pattern y and a permanent pattern AB. Based on the relationship of the CL morphology with the deciduous dentition, subdivision of the CL morphology into vermillion notch to two-thirds CL, two-thirds to subtotal CL, and complete CL appears to be an optimal subdivision. Our results indicate that a more detailed subdivision of the CL has clinical relevance and that critical factors in the pathogenesis of the CL are also critical for the odontogenesis.

Distinct DNA methylation profiles in subtypes of orofacial cleft

Background

Epigenetic 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.

Methods

In 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.

Results

We 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.

Conclusions

Our 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.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0362-2) contains supplementary material, which is available to authorized users.

Management of rare diseases of the Head, Neck and Teeth: results of a French population-based prospective 8-year study

BACKGROUND

In the last ten years, national rare disease networks have been established in France, including national centres of expertise and regional ones, with storage of patient data in a bioinformatics tool. The aim was to contribute to the development and evaluation of health strategies to improve the management of patients with rare diseases. The objective of this study has been to provide the first national-level data concerning rare diseases of the head, neck and teeth and to assess the balance between demand and supply of care in France.

METHODS

Centres of expertise for rare diseases record a minimum data set on their clinical cases, using a list of rare Head, Neck and Teeth diseases established in 2006. The present analysis focuses on 2008 to 2015 data based on the Orphanet nomenclature. Each rare disease RD "case" was defined by status "affected" and by the degree of diagnostic certainty, encoded as: confirmed, probable or non-classifiable. Analysed parameters, presented with their 95% confidence intervals using a Poisson model, were the following: time and age at diagnosis, proportions of crude and standardized RD prevalence by age, gender and geographical site. The criteria studied were the proportions of patients in Paris Region and the "included cases geography", in which these proportions were projected onto the other French Regions, adjusting for local populations.

RESULTS

In Paris Region, estimated prevalence of these diseases was 5.58 per 10,000 inhabitants (95% CI 4.3-7.1). At December 31st 2015, 11,342 patients were referenced in total in France, of whom 7294 were in Paris Region. More than 580 individual clinical entities (ORPHA code) were identified with their respective frequencies. Most abnormalities were diagnosed antenatally. Nearly 80% of patients recorded come to Paris hospitals to obtain either diagnosis, care or follow up. We observed that the rarer the disease, the more patients were referred to Paris hospitals.

CONCLUSIONS

A health network covering a range of aspects of the rare diseases problematic from diagnostics to research has been developed in France. Despite this, there is still a noticeable imbalance between health care supply and demand in this area.