Socio-Economic Status and Reproduction among Adults Born with an Oral Cleft: A Population-Based Cohort Study in Norway

Isolated oral clefts and school grades: population-based cohort study from Norway

OBJECTIVE

To compare school grades of adolescents in Norway born with isolated cleft with those of their unaffected peers.

DESIGN

Population-based cohort study.

SETTING

Norway.

PATIENTS

A total of 347 419 individuals born in Norway between 1986 and 1992, including 523 isolated cleft cases which were identified using data from Norway's two treatment centres. Individuals were followed from birth through compulsory school.

MAIN OUTCOME MEASURES

Grade point average (GPA) from middle school graduation (around the age of 16). Specific subject grades were also investigated.

RESULTS

Using a grade scale from 1-6, the observed mean GPA for the reference group was 3.99. Both cleft lip only (CLO) and cleft lip with cleft palate (CLP) had a mean GPA similar to the reference group (adjusted GPA differences from the reference with 95% CIs of 0.06 (-0.04 to 0.16) and -0.08 (-0.19 to 0.03), respectively). Cleft palate only (CPO) had a marginally lower GPA (adjusted GPA difference: -0.18 (-0.28 to -0.08)). These comparisons were consistent across specific subjects. Overall, the evidence suggests a larger difference in GPA between cases and controls in males compared with females. Females with CLO even had a higher estimated GPA than females in the reference group (adjusted GPA difference: 0.19 (0.013 to 0.36)). Grades were similar regardless of laterality of cleft lip (CLO or CLP).

CONCLUSION

In Norway, individuals born with isolated CLO or CLP did not have lower average school grades when graduating from middle school. Individuals born with isolated CPO had marginally lower grades.

Incidence, Risk Factors, and Mortality Associated With Orofacial Cleft Among Children in Ontario, Canada

IMPORTANCE

Orofacial cleft (OFC) is one of the most common congenital malformations, with a wide variation in incidence worldwide. However, population-based studies on the incidence of OFC in North America are lacking.

OBJECTIVES

To examine the incidence of OFC in Ontario, Canada, and to compare risk factors and mortality associated with children with OFC vs children without OFC.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study used health administrative data from the province of Ontario, Canada. Children with OFC who were born from April 1, 1994, to March 31, 2017, in Ontario were each matched to 5 children without OFC based on sex, date of birth (±30 days), and mother's age (±5 years). Analyses were conducted from September 2018 to January 2019.

EXPOSURES

Children born with OFC.

MAIN OUTCOMES AND MEASURES

Incidence of OFC over time and regional variation. Risk factors for OFC were assessed using 1-way analysis of variance for means, Kruskal-Wallis for medians, and χ2 tests for categorical variables. Adjusted Cox regression models were used to assess mortality.

RESULTS

From 1994 to 2017, 3262 children were born with OFC in Ontario, Canada, and they were matched to 15 222 children born without OFC. Incidence of OFC in Ontario was 1.12 cases per 1000 live births, with wide geographic variation and a lower incidence from 2004 to 2017 compared with 1994 to 2003 (1.02 vs 1.13 cases per 1000 live births; P = .002), especially for the subgroup with cleft palate (0.52 vs 0.44 cases per 1000 live births; P = .006). Children with OFC, compared with children without OFC, were more likely to be born prematurely (406 children [13.3%] vs 1086 children [7.1%]; P < .001; standardized difference, 0.21) and had lower mean (SD) birth weight (3215.3 [687.6] g vs 3382.6 [580.0] g; P < .001; standardized difference, 0.26). The mortality rate among children with OFC was higher than among matched children without OFC (hazard ratio, 10.60; 95% CI, 7.79-14.44; P < .001). When mortality was adjusted for the presence of congenital or chromosomal anomalies, the risk of death was not significantly different between children with OFC and those without OFC (hazard ratio, 1.35; 95% CI, 0.73-2.72).

CONCLUSIONS AND RELEVANCE

These findings suggest that incidence of OFC In Ontario, Canada, decreased from 1994 to 2017. Mortality in children with OFC was high, especially in the first 2 years of life, and was predominantly associated with the presence of other congenital or chromosomal anomalies. Further research is required to better understand the causes of wide geographical variations of OFC incidence and improve the survival of these patients.

A genome-wide scan of cleft lip triads identifies parent-of-origin interaction effects between ANK3 and maternal smoking, and between ARHGEF10 and alcohol consumption

Background: Although both genetic and environmental factors have been reported to influence the risk of isolated cleft lip with or without cleft palate (CL/P), the exact mechanisms behind CL/P are still largely unaccounted for. We recently developed new methods to identify parent-of-origin (PoO) interactions with environmental exposures (PoOxE) and now apply them to data from a genome-wide association study (GWAS) of families with children born with isolated CL/P. Methods: Genotypes from 1594 complete triads and 314 dyads (1908 nuclear families in total) with CL/P were available for the current analyses. Of these families, 1024 were Asian, 825 were European and 59 had other ancestries. After quality control, 341,191 SNPs remained from the original 569,244. The exposures were maternal cigarette smoking, use of alcohol, and use of vitamin supplements in the periconceptional period. Our new methodology detects if PoO effects are different across environmental strata and is implemented in the R-package Haplin. Results: Among Europeans, there was evidence of a PoOxSmoke effect for ANK3 with three SNPs (rs3793861, q=0.20, p=2.6e-6; rs7087489, q=0.20, p=3.1e-6; rs4310561, q=0.67, p=4.0e-5) and a PoOxAlcohol effect for ARHGEF10 with two SNPs (rs2294035, q=0.32, p=2.9e-6; rs4876274, q=0.76, p=1.3e-5). Conclusion: Our results indicate that the detected PoOxE effects have a plausible biological basis, and thus warrant replication in other independent cleft samples. Our demonstration of the feasibility of identifying complex interactions between relevant environmental exposures and PoO effects offers new avenues for future research aimed at unravelling the complex etiology of cleft lip defects.

A genome-wide scan of cleft lip triads identifies parent-of-origin interaction effects between ANK3 and maternal smoking, and between ARHGEF10 and alcohol consumption

Background: Although both genetic and environmental factors have been reported to influence the risk of isolated cleft lip with or without cleft palate (CL/P), the exact mechanisms behind CL/P are still largely unaccounted for. We recently developed new methods to identify parent-of-origin (PoO) interactions with environmental exposures (PoOxE) and applied them to families with children born with isolated cleft palate only. Here, we used the same genome-wide association study (GWAS) dataset and methodology to screen for PoOxE effects in the larger sample of CL/P triads. Methods: Genotypes from 1594 complete triads and 314 dyads (1908 nuclear families in total) with CL/P were available for the current analyses. Of these families, 1024 were Asian, 825 were European and 59 had other ancestries. After quality control, 341,191 SNPs remained from the original 569,244. The exposures were maternal cigarette smoking, use of alcohol, and use of vitamin supplements in the periconceptional period. The methodology applied in the analyses is implemented in the R-package Haplin. Results: Among Europeans, there was evidence of a PoOxSmoke effect for ANK3 with three SNPs (rs3793861, q=0.20, p=2.6e-6; rs7087489, q=0.20, p=3.1e-6; rs4310561, q=0.67, p=4.0e-5) and a PoOxAlcohol effect for ARHGEF10 with two SNPs (rs2294035, q=0.32, p=2.9e-6; rs4876274, q=0.76, p=1.3e-5). Conclusion: Our results indicate that the detected PoOxE effects have a plausible biological basis, and thus warrant replication in other independent cleft samples. Our demonstration of the feasibility of identifying complex interactions between relevant environmental exposures and PoO effects offers new avenues for future research aimed at unravelling  the complex etiology of cleft lip defects.

Eighteen-Year Follow-Up of 160 Consecutive Individuals Born With Unilateral Cleft Lip or Cleft Lip and Alveolus Treated by the Oslo Cleft Lip and Palate Team

OBJECTIVE

Describe patients born with unilateral cleft lip with or without cleft alveolus (CL±A) in relation to cleft severity and laterality, gender, associated anomalies and syndromes, number and type of lip- and nose operations, and time of alveolar bone graft (ABG) treatment in relation to dental status in cleft area.

MATERIALS AND METHODS

Patients included 220 children born with unilateral CL±A, born between 1988 and 1997 referred to the Oslo Cleft Lip and Palate Team. The data were collected retrospectively. All patients were followed up until 18 years of age.

RESULTS

Among all CL±A, 3.6% had recognized syndromes, 6.8% had associated anomalies, and in 89.6% CL±A was the only malformation. CL±A was more common, but not more severe, on the left side. Among the 160 individuals with CL±A without syndromes and associated anomalies, 66.9% had an isolated soft tissue CL, and 33.1% were diagnosed with a CL alveolus (CL+A). Male predominance was observed. Children with CL+A had more severe soft tissue clefts of the lip and underwent more lip and nose surgeries than children born with CL. The time of ABG was found to be at a younger age when the patient had a lateral incisor in the cleft area than when this tooth was missing.

CONCLUSION

Findings provide a reference for morphologic variations in CL±A, and insight into the surgical burden of care until the age of 18 years.

Associations Between Hypernasality, Intelligibility, and Language and Reading Skills in 10-Year-Old Children With a Palatal Cleft

Background:

This study investigated the associations between hypernasality and intelligibility, and language and reading skills in 10-year old children with a cleft palate ± lip.

Design:

Cross-sectional data collected during routine assessments of speech and language in a centralized treatment setting.

Participants:

Children aged 10, born with cleft palate ± lip from 4 birth cohorts (N = 123).

Outcome Measures:

Hypernasality and intelligibility: Swedish Articulation and Nasality Test-N; language: Language 6-16 (Sentence recall, Serial recall, Vocabulary); reading: word chain test and reading comprehension test.

Results:

A total of 71.3% of the children had no occurrence of hypernasality and 82.8% had intelligibility scores within the normal range. For all children with hypernasality and intelligibility within the normal range, reading and language scores were also within normal ranges. Children with presence of hypernasality had significantly lower language skills, with mean scores within the lower normal range. Children with reduced intelligibility had lower scores on reading comprehension.

Conclusions:

The findings highlight a possible association between hypernasality and language skills, and intelligibility and reading skills. Cleft teams should consider routine assessments of language and reading skills in children with speech impairment, in order to identify potential needs for intervention as early as possible.

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.