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.

Classifying common oral clefts: a new approach after descriptive registration.

OBJECTIVE: Using the Dutch Oral Cleft Registration, which records the morphology and topography of common oral clefts, a new classification based on the (patho)embryology of the primary and secondary palates was tested. DESIGN: Prospective observational study. SETTING: The fifteen cleft palate teams in the Netherlands register patients to the national registry. PATIENTS: All unoperated patients with common oral clefts reported between 1997 and 2006 inclusive were included. MAIN OUTCOME MEASURES: The classification is based on the pathoembryological events that ultimately result in various subphenotypes of common oral clefts. PATIENTS within the three categories cleft lip/alveolus (CL/A), cleft lip/alveolus and palate (CL/AP), and cleft palate (CP) were divided into three subgroups: fusion defects, differentiation defects, and fusion and differentiation defects. A timetable was constructed to relate the type of clefting to the time of derailment during embryonic development. RESULTS: 3512 patients were included. PATIENTS with CL/A showed 22% fusion defects, 75% differentiation defects, and 3% fusion and differentiation defects. CL/AP patients and CP patients mostly showed fusion defects (70% and 89%, respectively). We were able to relate almost all (over 90%) cleft subphenotypes to specific weeks in embryonic development. CONCLUSIONS: This classification provides new cleft subgroups that may be used for clinical and fundamental research. The subphenotypes of these subgroups originate from different time frames during embryonic development and different cell biological mechanisms, thereby enabling more accurate data for, e.g., gene identification and/or environmental factors.

Periconceptional folic acid associated with an increased risk of oral clefts relative to non-folate related malformations in the Northern Netherlands: a population based case-control study.

Periconceptional folic acid has been associated with a reduced risk of neural tube defects, but findings on its effect in oral clefts are largely inconclusive. This case-control study assesses the effects of periconceptional folic acid on cleft risk, using complementary data from the Dutch Oral Cleft Registry and a population-based birth defects registry (Eurocat) of children and foetuses born in the Northern Netherlands between 1997 and 2009. Cases were live-born infants with non-syndromic clefts (n = 367) and controls were infants or foetuses with chromosomal/syndromal (n = 924) or non-folate related anomalies (n = 2,021). We analyzed type/timing/duration of supplement use related to traditional cleft categories as well as to their timing (early/late embryonic periods) and underlying embryological processes (fusion/differentiation defects). Consistent supplement use during the aetiologically relevant period (weeks 0-12 postconception) was associated with an increased risk of clefts (adjusted odds ratio 1.72, 95% confidence interval 1.19-2.49), especially of cleft lip/alveolus (3.16, 1.69-5.91). Further analysis systematically showed twofold to threefold increased risks for late differentiation defects-mainly clefts of the lip/alveolus-with no significant associations for early/late fusion defects. Effects were attributable to folic acid and not to other multivitamin components, and inclusion of partial use (not covering the complete aetiologically relevant period) generally weakened associations. In conclusion, this study presents several lines of evidence indicating that periconceptional folic acid in the Northern Netherlands is associated with an increased risk of clefts, in particular of cleft lip/alveolus. This association is strengthened by the specificity, consistency, systematic pattern, and duration of exposure-response relationship of our findings, underlining the need to evaluate public health strategies regarding folic acid and to further investigate potential adverse effects.

Regional variation in prevalence of oral cleft live births in the Netherlands 1997-2007: time-trend analysis of data from three Dutch registries.

The Eurocat registry Northern Netherlands (NNL) has been used in regional context, as well as in national/international context, to describe the epidemiology of oral clefts (OC). However, the region NNL seems to have prevalence data different from Dutch national registries and certain other European areas. This may be due to differences in registration methods or geographical variation. To investigate whether the prevalence of OC live births varies regionally in the Netherlands, we established time trends for NNL and the rest of the Netherlands over 1997-2007 using data from two national registries (the OC Registry and The Netherlands Perinatal Registry) and a regional registry (Eurocat NNL). We found that the overall live-birth prevalence-comprising cleft lip/alveolus ± cleft palate and cleft palate only-was significantly higher in NNL (15.1-21.4 per 10,000) than in the rest of the Netherlands (13.2-16.1 per 10,000). None of the registries showed significant trends for NNL, whereas both national registries showed that the live-birth prevalence of cleft lip/alveolus ± cleft palate decreased significantly in the rest of the Netherlands. Despite some differences in prevalence between the registries, they showed similar regional variation in prevalence and trends. In conclusion, the prevalence of OC live births varies significantly in the Netherlands, not only between but also within registries. This underlines that extrapolation of regional cleft data should be done with caution. To further investigate OC etiology and evaluate preventive strategies, future studies should consider geographical differences-between and within countries-regarding the various cleft sub-phenotypes among live births, stillbirths, and pregnancy terminations.

Validation of the Dutch registry of common oral clefts: quality of recording specific oral cleft features.

OBJECTIVE: Since 1997, common oral clefts in the Netherlands have been recorded in the national oral cleft registry using a unique descriptive recording system. This study validates data on the topographic-anatomical structure, morphology, and side of individual anomalies of the primary palate and secondary palate that form the oral cleft. DESIGN: Validation study. SETTING: All 15 Dutch cleft palate teams reporting presurgery oral cleft patients to the national registry. PATIENTS: A random sample of 250 cases registered in the national database with oral clefts from 1997 through 2003; of these, 13 cases were excluded. MAIN OUTCOME MEASURES: By linking registry data with clinical data, we identified differential recording rates by comparing the prevalence, and we measured the degree of agreement by computing validity and reliability statistics. RESULTS: The topographic-anatomical structures (lip, alveolus, and hard and soft palates) of the anomalies had near-perfect interdatabase agreement with a sensitivity of 88% to 99%. However, when analyzing the individual anomalies in detail (morphology and side), validity decreased and depended on morphological severity. This association was most evident for anomalies of the secondary palate. For example, sensitivity was higher for "complete cleft hard palate" (92%) than for "submucous cleft hard/soft palate" (69%). CONCLUSIONS: Overall, the validity of Dutch registry data on oral clefts is good, supporting the feasibility of this unique recording system. However, when analyzing oral cleft data in detail, the quality appears to be related to anatomical location and morphological severity. This might have implications for etiologic research based on registry data and for guidelines on neonatal examination.

Validation of the NVSCA registry for common oral clefts: study design and first results.

OBJECTIVE: Since 1997 the Dutch Association for Cleft Palate and Craniofacial Anomalies (NVSCA) has maintained a national registry of congenital craniofacial anomalies. This study validates data on three common oral cleft categories (cleft lip/alveolus = CL/A; cleft lip/alveolus and palate = CL/AP; and cleft palate = CP) and general items. DESIGN: Retrospective observational study. SETTING: All 15 Dutch cleft palate teams registered presurgery patients with common oral clefts (n = 2553) from 1997 to 2003. PATIENTS: A random sample of 250 cases was used; 13 cases were excluded. MAIN OUTCOME MEASURES: The corresponding medical data were reviewed; these medical data served to validate the NVSCA registry data. Prevalence comparisons, 2 x 2 tables and validity measures were performed. RESULTS: The cleft categories most accurately recorded were CL/A and CP. Both categories had an observed agreement of 98%, kappa of 0.94, and a sensitivity and specificity of 97%. Cleft lip/alveolus and palate had an observed agreement of 95%, kappa of 0.89, a sensitivity of 90%, and a specificity of 99%. Regarding the general items, observed agreement and kappa were highest for adoption/foster child (99%; 0.76) and lowest for remarks about pregnancy (63%; 0.20). Sensitivity ranged from 25% (consanguinity) to 97% (white mother) and specificity was high for all items (>93%) except for white father and mother (approximately 35%). CONCLUSIONS: The NVSCA registry is a valuable tool for quality improvement and research because validity on all three common oral cleft categories is very good. Validity on the general items is reasonable to satisfying and appears to be related to the type of information.

Decreasing prevalence of oral cleft live births in the Netherlands, 1997-2006.

OBJECTIVES: The number of new oral cleft patients has fallen in the Netherlands. This may be explained by two hypotheses: (1) greater prenatal detection of congenital anomalies has led to more pregnancy terminations and (2) increased folic acid use has reduced the oral cleft risk. Both hypotheses would mainly apply to the category cleft lip/alveolus ± cleft palate (CL±P), since, unlike cleft palate only (CP), CL±P can be detected prenatally by two-dimensional (2D) ultrasound and develops during the period recommended for folic acid use. The authors aimed to determine trends in prevalence over 1997-2006 and to evaluate the hypotheses by stratifying trends by cleft category. METHODS: This study was a time-trend analysis of infants born alive with oral clefts in the Netherlands during 1997-2006 and registered in the national oral cleft registry. The authors calculated prevalence rates and the estimated annual percentage change (EAPC) for all oral clefts and the two categories. RESULTS: In 1997-2006, 3308 infants out of 1 970 872 live births had oral clefts, an overall prevalence per 10 000 live births of 16.8 (CL±P: 11.3; CP: 5.5). Time-trend analysis showed that the prevalence of all oral clefts decreased (EAPC -1.8%; 95% CI: -3.0% to -0.6%), as did the CL±P prevalence (EAPC -2.3%; 95% CI: -3.8% to -0.9%). No significant trends were found for the CP prevalence. CONCLUSIONS: Because the live-birth prevalence of CL±P decreased, that of all oral clefts decreased. These findings are in line with both hypotheses and may therefore have implications for prenatal counselling and folic acid policy.