The further epidemiological differentiation of cleft lip and palate: a population study of clefts in King County, Washington, 1956-1965

Cleft lip and/or palate mortality trends in the USA: a retrospective population-based study

BACKGROUND

Cleft lip and/or palate (CL/P) is one of the most common congenital anomalies worldwide. Although CL/P management may require a series of interventions, mortality resulting from CL/P alone is rare. This study aims to examine recent trends of CL/P mortality rates in the USA.

METHODS

A retrospective population-based study was conducted using official US birth and death certificate data from the Centers for Disease Control and Prevention from 2000 to 2019. Annual mortality rates per 1000 births with CL/P were calculated across sex and racial groups. Multivariable logistic regression models estimated the effects of sex and race on the risk of mortality with CL/P, and linear regression models were used to examine temporal changes in mortality rate across sex and race.

RESULTS

From 2000 to 2019, 1119 deaths occurred in patients with documented CL/P, for an overall incidence of 20.3 deaths per 1000 births with CL/P (95% CI 18.9 to 22.8). Of these, Patau syndrome was the listed cause of death in 167 cases (14.9%). Black individuals (OR 1.93, 95% CI 1.85 to 2.01), Hispanic (1.54, 1.49 to 1.58) and American Indian individuals (1.28, 1.20 to 1.35) were at a greater risk of CL/P mortality compared with white individuals. Additionally, females were also at a greater risk (1.35, 1.21 to 1.49). A significant upward trend in CL/P mortality was observed in Hispanic (r2=0.70, p<0.01) and American Indian individuals (r2=0.81, p<0.01) from 2000 to 2019.

CONCLUSIONS

Cleft birth and mortality surveillance is essential in healthcare and prevention planning. Future studies are required to understand the differences in CL/P mortality rates across various sociodemographic groups.

Epidemiology of Nonsyndromic, Orofacial Clefts in Texas: Differences by Cleft Type and Presence of Additional Defects

To describe the current epidemiology of nonsyndromic cleft palate alone (CP) and cleft lip with or without cleft palate (CL ± P) in Texas and examine differences in the characteristics of infants with CP and CL ± P based on the presence/absence of additional defects.

We used data from the Texas Birth Defects Registry, a statewide active birth defect surveillance system, from 1815 cases with CP and 5066 with CL ± P, without a syndrome diagnosis (1999-2014 deliveries). All live births in Texas were used for comparison. Poisson regression was used to calculate crude and adjusted prevalence ratios (aPR) for each characteristic, separately for each cleft subphenotype.

The prevalence of CL ± P and CP in our study was estimated as 8.3 and 3.0 per 10 000 live births, respectively. After adjusting for several characteristics, several factors were associated with CL ± P, CP, or both, including infant sex and maternal race/ethnicity, age, smoking, and diabetes. There were several differences between infants with isolated versus nonisolated clefts. For example, maternal prepregnancy diabetes was associated with an increased prevalence of CL ± P (aPR 7.91, 95% confidence interval [CI]: 5.53, 11.30) and CP (aPR 3.24, 95% CI: 1.43, 7.36), but only when additional defects were present.

Findings from this study provide a contemporary description of the distribution of orofacial clefts in Texas accounting for differences between isolated and nonisolated clefts. They may contribute to increasing our understanding of the etiology of CP and CL ± P.

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.

An Epidemiologic Study of Isolated Cleft Lip, Palate, or Both in Victoria, Australia from 1983 to 2000

Objective

To report the epidemiological characteristics of isolated cleft lip, cleft palate or both (CL ± P and CP) using population-based data in Victoria, Australia.

Design

Descriptive study of a cohort of children born between 1983 and 2000 notified to the Victorian Birth Defects Register by multiple ascertainment sources.

Participants

Data were collected on patients identified with CL ± P and CP without associated defects classified as live births, stillbirths, neonatal deaths, and terminated pregnancies < 20 weeks’ gestation following prenatal identification. Information was collected on sex, plurality, maternal age, and country of birth.

Results

The overall prevalence (per 10,000 pregnancies) of CL ± P was 7.8 (95% confidence interval [CI] = 7.30, 8.33; cleft lip [CL] 3.3; 95% CI = 2.97, 3.65, CL+P 4.5; 95% CI = 4.13, 4.91) and cleft palate (CP), 4.3 (95% CI = 3.89, 4.66). The prevalence of CL + P was higher among stillbirths, neonatal deaths, and terminated pregnancies than CL (without CP) and CP. Boys were at greater risk than girls for CL ± P and girls at greater risk than boys for CP. Regardless of cleft type, there was a nonsignificant excess of clefts among singleton births than multiple births and no related effects of maternal age or country of birth.

Conclusions

The prevalence of isolated CL ± P and CP in Victoria parallels other population-based studies of the same conditions. Inclusion of stillbirths, neonatal deaths, and terminations had little impact on rates. The effect of sex and plurality on cleft type is consistent with the literature, but the effects of maternal age and country of birth remain equivocal. Further studies focusing on certain ethnic groups are warranted to explain the higher rates observed.

Analysis of the genetic ancestry of patients with oral clefts from South American admixed populations

Increased susceptibility to cleft lip, with or without cleft palate (CL±P) has been observed in South America, as related to Amerindian ancestry, using epidemiological data, uniparental markers, and blood groups. In this study, it was evaluated whether this increased risk remains when Amerindian ancestry is estimated using autosomal markers and considered in the predictive model. Ancestry was estimated through genotyping 62 insertion and deletion (INDEL) markers in sample sets of patients with CL±P, patients with cleft palate (CP), and controls, from Patagonia in southern Argentina and Belém in northern Brazil. The Amerindian ancestry in patients from Patagonia with CL±P was greater than in controls although it did not reach statistical significance. The European ancestry in patients with CL±P from Belém and in patients with CP from Belém and Patagonia was higher than in controls and statistically significant for patients with CP who were from Belém. This high contribution of European genetic ancestry among patients with CP who were from Belém has not been previously observed in American populations. Our results do not corroborate the currently accepted risks for CL±P and CP estimated by epidemiological studies in the North American populations and probably reflect the higher admixture found in South American ethnic groups when compared with the same ethnic groups from the North American populations.

Long-term survival for infants born with orofacial clefts in Western Australia

BACKGROUND

Only two population-based studies have reported survival beyond 15 years for individuals with orofacial clefts (OFC), and only for individuals with isolated OFC. Compared with the general population, long-term survival was similar for individuals with cleft lip only, and lower for individuals with cleft palate only. Results for those born with isolated cleft lip and cleft palate were inconsistent.

METHODS

Using linked population-based health data, including a congenital anomaly register with active surveillance and diagnoses up to 6 years, we compared survival at 1, 5, and 20 years for infants born 1980 to 2010 with, and without OFC.

RESULTS

Of the 8112 live born infants in the cohort, 186 died before 20 years; most (81%) died during infancy. Compared with infants without OFC, infants born with all types of isolated OFC ± additional minor anomalies had similar infant survival (around 99%), but we found lower survival for infants with all cleft types and an additional major anomaly (66-84%). From 1 to 5 years, only infants with cleft palate only and an additional major anomaly had lower survival (97%) compared with children without OFC (99.9%). From 5 to 20 years, children with all cleft types, with or without additional major anomalies had similar survival to children without OFC (98-100%).

CONCLUSION

Parents with a child diagnosed with an OFC ± additional minor anomalies only can be reassured that the OFC does not influence survival rates in infancy, or long-term. Infant survival was lower only for children with OFC and additional major anomalies.

Elevated Infant Mortality Rate among Dutch Oral Cleft Cases: A Retrospective Analysis from 1997 to 2011

Objectives: First, to determine the infant mortality rate (IMR) for Dutch patients with isolated oral clefts (OC) as well as for patients with clefts seen in association with other malformations. Second, to conduct a similar analysis per cleft type: cleft lip with or without cleft palate (CP), CP (including Robin sequence). Third, to examine the underlying causes of death.

Material and Methods: A retrospective review of the charts of patients with OC born in the period 1997–2011 and treated in three regional cleft centers in the Netherlands.

Results: One thousand five hundred thirty patients with OC were born during the study period and treated in the cleft centers. The overall IMR for all clefts was 2.09%, significantly higher than the general Dutch IMR of 0.45%. In a subanalysis per cleft type, the IMRs were 1.22, 1.38, 2.45, and 3.62% for cleft lip, cleft lip with CP, CP, and Robin sequence, respectively. The mortality rates for isolated OC did not differ significantly from the general Dutch rate. Causes of death were congenital malformations of the heart in 40.6%, airway/lungs in 15.6%, nervous system in 15.6%, infectious disease in 12.5%, and other or unknown in 15.6%.

Conclusion: The elevated IMR observed in Dutch patients with OC is almost exclusively caused by associated congenital malformations. After diagnosis of an oral cleft an in-depth medical examination and a consult by the pediatrician and clinical geneticist is imperative to instigate the appropriate medical management.

Classification, epidemiology, and genetics of orofacial clefts

Orofacial clefts (OFCs) include a broad range of facial conditions that differ in cause and disease burden. In the published literature, there is substantial ambiguity in both terminology and classification of OFCs. This article discusses the terminology and classification of OFCs and the epidemiology of OFCs. Demographic, environmental, and genetic risk factors for OFCs are described, including suggestions for family counseling. This article enables clinicians to counsel families regarding the occurrence and recurrence of OFCs. Although much of the information is detailed, it is intended to be accessible to all health professionals for use in their clinical practices.

Stability of Orofacial Clefting Rate in Alberta, 1980–2011

Objective

To determine the prevalence and trends of orofacial clefts in Alberta (Canada) over a 33-year period (1980 through 2011) and to determine whether the trends differ for subcategories of orofacial clefts for the period from 1997 through 2011.

Design

A prevalence study based on the Alberta Congenital Anomalies Surveillance System, which has multiple sources of ascertainment, capability of verification, and an upper age limit of 1 year.

Inclusion

All live born and stillborn babies and fetal deaths less than 20 weeks' gestation (including terminations of pregnancy) born in Alberta of mothers who reside in Alberta.

Results and Conclusions

Rates for cleft lip with or without cleft palate and cleft palate only have been very stable over the 33-year period (1980 through 2011). These rates include all clefts (isolated, syndromes, recognizable conditions, chromosomal and multiple congenital anomalies). Ascertainment of fetal deaths less than 20 weeks' gestation began in 1997. There are trends for the 1997 through 2011 cohort with a marginally significant increase for cleft lip with or without cleft palate in the isolated category and a significant decrease for cleft palate, mainly in the associated groups. The impact of folic acid fortification and/or multivitamins/folic acid supplementation reports in the literature have shown no consensus with respect to a change in the prevalence of orofacial clefts. It is unclear whether folic acid fortification has had any impact in Alberta.

Incidence of Cleft Pathology in Greater New Orleans before and after Hurricane Katrina

Background

Reports after the 2005 Hurricane Katrina have documented an increase in stress reactions and environmental teratogens (arsenic, mold, alcohol).

Objective

To assess the incidence of cleft pathology before and after the hurricane, and the distribution of cleft cases by gender and race.

Methods

Retrospective chart review of cleft lip with or without cleft palate (CUP) and cleft palate (CP) cases registered with the Cleft and Craniofacial Team at Children's Hospital of New Orleans, the surgical center that treated cleft cases in Greater New Orleans between 2004 and 2007. Live birth data were obtained from the Louisiana State Center for Health Statistics.

Results

The incidence of cleft cases, beginning 9 months after the hurricane (i.e., June 1, 2006) was significantly higher compared with the period before the hurricane (0.80 versus 1.42; p = .008). Within racial group comparisons showed a higher incidence among African Americans versus whites (0.42 versus 1.22; p = .01). The distribution of CUP and CP cases by gender was significant ( p = .05).

Conclusion

The increase in the incidence of cleft cases after the hurricane may be attributable to increased stress and teratogenic factors associated with the hurricane. The increase among African Americans may have been due to comparatively higher exposure to environmental risk factors. These findings warrant further investigation to replicate the results elsewhere in the Gulf to determine whether there is a causal relationship between environmental risk factors and increased cleft pathology.

Elevated infant mortality rates among oral cleft and isolated oral cleft cases: a meta-analysis of studies from 1943 to 2010

Objective : To review available published literature in order to obtain a more comprehensive assessment of the association between infant mortality and oral clefts, overall and isolated. Design : A wide-ranging search of published studies relating infant mortality rates to oral clefts and congenital malformations was conducted, yielding applicable data sets. Settings of the included studies varied to a limited extent, although all were conducted within high-income countries with superior health indicators. These results were tabulated and meta-analyzed. Random effects odds ratios comparing each data set with its respective population have been used to account for differing settings and specific infant mortality rates. Results : Nine articles with relatable data were included in these meta-analyses. The calculated odds ratio of infant mortality associated with oral cleft cases, including those with associated malformations, was substantial: 9.466 (95% confidence interval, 6.153 to 14.560). Excluding oral cleft cases with associated malformations, the odds ratio, although lower, was still significant: 2.073 (95% confidence interval, 1.390 to 3.092). Conclusions : Compared with the overall population, infants with oral clefts have nine times the odds of dying within the first year of life. Furthermore, even without additional malformations, infants with oral clefts are still twice as likely to die before 1 year of age. Current research points to a substantially higher relative risk of infant mortality among oral cleft cases in developing countries. Additional research is essential to determine the sources of these raised infant mortality rates and possible interventions to decrease them.

Parental age as a risk factor for non-syndromic oral clefts: a meta-analysis

OBJECTIVES

A meta-analysis was conducted to assess the relationship between parental age and the occurrence of non-syndromic oral clefts. The questions addressed if younger or older mothers and fathers have an increased risk of having a child with non-syndromic oral clefts.

DATA

Data from cohort studies, case-control, cross-sectional and prevalence studies in which the association between parental age and oral clefts was investigated were analysed. Only studies on oral clefts not associated with syndromes or other anomalies were considered.

SOURCES

An electronic literature search were conducted in Medline, Embase, LILACS, SciELO, SCOPUS and the Cochrane library databases to identify original research published until November 2010. References of the selected articles were also searched.

STUDY SELECTION

The initial database search identified 4623 citations and according to eligibility criteria 80 articles were submitted to quality assessment. In 13 studies measures of association could be extracted for meta-analysis.

CONCLUSION

Our findings suggest that fathers forty years of age or older had a 58% higher probability of having a child with cleft palate compared to those aged between 20 and 39 years. The probability of mothers aged between 35 and 39 years having a child with cleft palate was 20% higher in comparison with those between 20 and 29 years-old, whilst for those aged 40 years or more this probability was 28% higher compared to those aged between 20 and 29 years. Mothers aged 40 years or over were 1.56 times more likely to have a newborn with cleft lip with or without palate compared to those aged between 20 and 29 years. No evidence of association between early maternal and paternal age with occurrence of oral clefts was observed.

Orofacial cleft malformations: Associations with maternal and infant characteristics in Washington State

BACKGROUND

To characterize the prevalence of orofacial cleft malformations and investigate variations in prevalence according to maternal and infant characteristics, we analyzed a cohort of 298,138 live births delivered between 1987 and 1990 to residents of Washington State.

METHODS

Infants with cleft defects were identified using a statewide, population-based birth defects registry. Information on infant and maternal characteristics was obtained from Washington State birth certificates. Multiple logistic regression analysis was used to measure the association between potential risk factors and orofacial clefts. Cleft lip with or without cleft palate (CL +/- CP) and cleft palate (CP) were analyzed separately, depending on the presence or absence of other defects.

RESULTS

We identified 608 infants with cleft defects. The prevalences of isolated and non-isolated CL +/- CP were 0.87 and 0.30 per 1,000 live births, respectively. The prevalences of isolated and non-isolated CP were 0.34 and 0.54 per 1,000 live births, respectively. Compared with mothers aged 25-29 years, mothers aged < 20 years were twice as likely to have an infant with isolated CL +/- CP (RR = 2.0; 95% CI 1.3, 2.9). Compared to white mothers, black mothers were more likely to have an infant with non-isolated CL +/- CP (RR = 2.8; 95% CI 1.2, 6.6).

CONCLUSIONS

The prevalences of orofacial clefts in Washington State in 1987-90 were similar to those of other states. This study is among the first to report a greater relative risk for isolated CL +/- CP among the infants of mothers < 20 years compared to older mothers.

Maternal age and oral clefts: a reappraisal

OBJECTIVE

The aim of the study was to test the hypothesis that increased maternal age is associated with a higher risk of having a child with oral clefts.

STUDY DESIGN

A meta-analysis of 8 population-based studies with information regarding live birth and oral clefts was performed.

RESULTS

No association between increased maternal age and isolated oral clefts was found.

CONCLUSION

Oral clefts occurrence is not correlated with increasing maternal age, and inclusion of data mixing isolated and syndromic cases can confound the analysis and must be avoided.

Birth order and oral clefts: a meta analysis

BACKGROUND

There is evidence that late birth order is associated with some complex disorders. For orofacial clefts there is no consensus as to whether increased birth order is associated or not. A meta-analysis of published data on cleft lip or cleft palate (CL/P and CP) was carried out to ascertain whether there is an increased risk for children of high birth order to have an oral cleft.

METHODS

All data available with information regarding the frequency of live births and CL/P and CP cases by birth order (1, 2, 3, and 4 or more) were included in the analysis, and the birth order category "1" was considered to be with no risk (OR = 1.0).

RESULTS

Children with higher birth order are more likely to have CL/P and CP with odds ratios increasing with birth order to a peak of 3.0 in children birth order "4 or more." Results are not different when isolated and syndromic cases are combined.

CONCLUSIONS

CL/P and CP occurrence is correlated with increasing birth order. Further studies, taking into consideration sample size and factors such as income status, race, paternal age, vitamin intake, and social habits, should be done to determine conclusively the association between birth order and oral clefts.

Descriptive epidemiology of nonsyndromic cleft lip with or without cleft palate in Shanghai, China, from 1980 to 1989

OBJECTIVE

The purpose of this study was to characterize nonsyndromic cleft lip with or without cleft palate (CL+/- CP) in an Asian population.

DESIGN

Birth prevalence was assessed in a large birth series in Shanghai, China. A 1:3 sex-age-hospital matched case-control design was used to assess the effects of parental ages and pregnancy history on risk of CL+/- CP.

PARTICIPANTS

Records of live births from 1980 to 1989 in 22 hospitals in Shanghai, China, were reviewed, comprising 541,504 consecutive births, which is by far the largest such Chinese sample ever investigated. The case-control study included 528 (308 male, 220 female) nonsyndromic CL+/- CP cases and 1,563 (912 male, 651 female) controls.

RESULTS

From 1980 to 1989, the overall birth prevalence was 1.2 per 1,000 live births with statistically significant seasonal variation (more CL+/- CP births in January to July). The overall male:female ratio was 1.40:1. For males, statistically significant associations were identified with maternal age for the most severe clefts (bilateral overall, and also bilateral CL+CP subgroup). For females, statistically significant association was shown for pregnancy age with birth order (overall and in most subgroups).

CONCLUSIONS

The birth prevalence of CL+/- CP in this Asian population was similar to published Caucasian rates. The observed seasonal variation would be consistent with possible environmental factors. Significant associations with maternal age, pregnancy age, and birth order warrant additional study of pregnancy history in Asian CL+/- CP.

Racial and ethnic variations in the prevalence of orofacial clefts in California, 1983-1992

To investigate variations in the prevalence of oral cleft anomalies according to parental race and ethnicity and maternal country of birth, the authors analyzed a cohort of 2,221,755 live births and fetal deaths delivered between 1983 and 1992 to residents of California. A total of 2,329 cleft lip with or without cleft palate (CL +/- P) cases and 1,475 cleft palate alone (CP) cases were identified by the California Birth Defects Monitoring Program, a population-based registry. Compared to Whites, the prevalence of CL +/- P was lower among African Americans (prevalence ratio (PR) = 0.56, 95% confidence interval (CI) = 0.45-0.69), higher among Native Americans (PR = 1.81, CI = 1.20-2.69), and the same among the Japanese (PR = 1.07, CI = 0.62-1.82) and Chinese (PR = 0.96, CI = 0.71-1.29). The risk of CL +/- P was slightly lower among the offspring of foreign-born Chinese women relative to U.S.-born Chinese women (PR = 0.71, CI = 0.33-1.57), and slightly higher among foreign-born Filipinos relative to their U.S.-born counterparts (PR = 1.37, CI = 0.57-3.53), although confidence intervals around these risk estimates were wide owing to sparse data. For CP, lower prevalences were observed among African Americans (PR = 0.72, CI = 0.58-0.91) and Hispanics (PR = 0.77, CI = 0.67-0.87) than among Whites. The risk of CP was higher among foreign-born Filipinos compared to U.S.-born Filipinos (PR = 1.52, CI = 0.58-4.33), although the confidence interval around this estimate included unity. These prevalence variations may reflect differences in both environmental and genetic factors affecting clefting risk.

First year-of-life mortality among infants with oral clefts: New York State, 1983-1990

This study examined the mortality experience of children with oral clefts using the New York State Congenital Malformations Registry. Infants born in the years 1983 to 1990 to New York residents, diagnosed with an oral cleft and matched to their birth certificate were included in the analysis. Children with oral clefts were compared to a sample of live births from the years 1983 to 1990 without malformations. Children with cleft palate without additional malformations had a statistically nonsignificant adjusted risk of 1.2 when compared to children with no malformations. Children with cleft lip with or without cleft palate had a 1.1 adjusted risk. However, 35% of children with oral clefts had associated malformations and experienced much higher mortality. Children with oral clefts should be carefully evaluated for additional malformations; if none are found, their mortality appears not to be elevated.

Maternal age and oral cleft malformations: data from a population-based series of 576,815 consecutive livebirths

It has been suggested that older mothers are more likely to have a child with isolated cleft palate (CP) or cleft lip +/- cleft palate (CL +/- CP), but most of these studies have been based on fairly small sample sizes. Data from a population-based registry with multiple sources of case ascertainment were used to examine any association of maternal age with the incidence of these defects in infants without other congenital anomalies. The study group consisted of all cases with CP or CL +/- CP without other congenital anomalies from a series of over half a million consecutive livebirths during the period 1966 to 1981 inclusive in British Columbia. During the study period, the overall incidences of isolated CP and isolated CL +/- CP per 10,000 livebirths were 3.9 and 8.2, respectively. No association with maternal age was found when either isolated CP or isolated CL +/- CP was analyzed as a group. When analyzed by sex, and by CP or CL +/- CP, no significant maternal-age effect was observed for males and females with CP or CL +/- CP. Our population-based data, therefore, do not show that older mothers are more likely to have a child with cleft palate, or cleft lip +/- cleft palate.

The contribution of maternal epilepsy and its treatment to the etiology of oral clefts: a population based case-control study

The associations between maternal epilepsy and anticonvulsant drug therapy with the risk of oral clefts in the offspring were investigated using data from a population-based case-control study. Cases included 238 infants with cleft lip +/- cleft palate (CLP) and 107 infants with cleft palate (CP) ascertained through the Metropolitan Atlanta Congenital Defects Program (MACDP) between 1968 and 1980. Controls included 3029 population-based normal infants. Histories of maternal epilepsy and drug therapy during pregnancy were compared between cases and controls using maternal interviews and reviews of hospital medical records. Maternal epilepsy was associated with increased risk of nonsyndromic CLP (OR = 3.78, 95% C.I. 1.65-7.88), and less with CP (OR = 1.75, 95% C.I. 0.20-6.99). Therapy during pregnancy was associated with the greatest excess risk (CLP OR = 7.77, C.I. 2.02-26.0; CP OR = 3.61, C.I. 0.08-26.5). The use of polytherapy was associated with the highest risk (CLP OR = 10.5, C.I. 1.52-59.9). Adjustment for potential confounding variables in the study did not change these findings. In this well-defined population, maternal epilepsy and its treatment account for a small proportion of nonsyndromic oral clefts (attributable fraction CLP = 3.3%, CP = 0.9%).

Genetic-epidemiologic study of omphalocele and gastroschisis: evidence for heterogeneity

On the basis of clinical manifestations, epidemiologic characteristics, and the presence of additional malformations, omphalocele (OM) and gastroschisis (GA) are considered casually and pathogenetically distinct abdominal wall defects. More than 50% of infants with OM have additional defects, but only about 15% of those with GA do. To evaluate whether there is heterogeneity between isolated and multiply affected cases of OM and GA, we analyzed epidemiologic characteristics and familial risks of major defects for 82 OM and 81 GA cases drawn from a population-based study in the Maryland-Washington, DC-Northern Virginia area and born from 1980 through June 1987. We examined year of birth, sex, race, and maternal age distributions after stratifying the infants into isolated and multiple defect groups. We found significant differences in maternal age between cases with isolated OM and GA, but not between cases with GA or OM who had other defects. Using regressive logistic models, we analyzed familial aggregation of birth defects among relatives of infants with OM and GA. An autosomal recessive model of inheritance was found to be the most parsimonious explanation for the families of infants with isolated OM or GA. However, for families of infants with multiple defects, a sporadic or nongenetic model fit best. These findings are not only useful for estimating familial risk of major birth defects, but they also suggest further heterogeneity of infants with OM and GA according to the presence of other malformations.

Characteristics of new patients at Illinois cleft palate teams

The Illinois Association of Craniofacial Teams (IACT) surveyed all new patient visits to member teams in an effort to assess the needs of patients in Illinois. The survey determined the number of patients, their age at initial visit, the location and status of their defect, and their history of team visits. Four hundred eighty new patient visits were recorded. The number of patients was substantially lower than expected, and the large majority of older children seeing a team for the first time had repaired defects. It is concluded that the main opportunity for improving the quality of care for patients with clefts in Illinois may be in increasing the use of cleft palate teams.

Isolated oral cleft malformations: associations with maternal and infant characteristics in a California population

Data on isolated oral cleft malformations from a birth defects registry covering a large population base were examined to describe potential associations with maternal and infant characteristics. Infants with cleft palate (CP) were analyzed separately from infants with cleft lip with or without cleft palate (CLP). The prevalence of isolated CLP per 1,000 births was 0.741, approximately twice the prevalence of isolated CP, which was 0.383. Male infants were more likely to be born with CLP (OR = 1.9) but less likely to be born with CP (OR = 0.56) than were females. Women 39 years or more of age were twice as likely as 25-29 year olds to have a child with either type of cleft. Black, nonhispanic infants had a lowered risk for CLP compared to white, nonhispanics (OR = 0.40). These risks were found to be independent of each other based on multivariate analyses. Associations with either type of cleft malformation were not observed for plurality, number of previous live births, and maternal birthplace.

Clinical/epidemiological analysis of malformations

To investigate the heterogeneity of congenital malformations, we analyzed the distribution of 14 selected anomalies among 11,421 children with isolated defects and with different patterns of multiple congenital anomalies (MCA). Our study showed a marked variability in the distribution of each of these malformations. For example, although anophthalmia/microphthalmia, cleft palate, and limb deficiency were observed in all etiological categories of syndromes, no case with anencephaly was identified among the 1,244 children with different syndromes. Diaphragmatic hernia, esophageal atresia +/- tracheoesophageal fistula, and gastroschisis were not found in any monogenic syndrome in this sample. These observations may be of help to the clinician in the evaluation of individual children with MCA.

Maternal cigarette smoking and oral clefts: a population-based study

Analyses of 1984 data from the Maryland Birth Defects Reporting and Information System indicate that mothers of infants with oral clefts (cleft lip with or without cleft palate; and cleft palate) smoked more during pregnancy than mothers of infants with other defects (odds ratio OR of 2.56 and 2.39, respectively). There was a dose-response relation between the daily amount smoked and the risk of clefting. Adjustment for available confounding variables did not account for the association between smoking and oral clefts.

Congenital anomalies in American Indians of British Columbia

Birth prevalences of congenital anomalies in the American Indians of British Columbia are compared with those of the total British Columbia population. This study is based on data from the British Columbia Health Surveillance Registry for a 16-year period (1966-1981) judged to be the most reliable reporting period in the 35-year history of the registry. The overall congenital anomaly frequency is lower in Indians than in the general population (45 versus 60 per 1,000 livebirths). The Indian rates for individual anomalies are lower than the corresponding general population rates with the exception of orofacial clefting and congenital heart defects. Defects of the central nervous system in both populations are comparable. There is a striking paucity of hypospadias, other anomalies of the genital organs and foot deformities in Indian males. It is suggested that the differences in the congenital anomaly rates between the American Indians and the non-Indians of British Columbia may reflect genetic differences between the two groups, but differences in ascertainment and infant mortality probably also play a role.

Fetal mortality in oral cleft families(IV): the "doubling effect"

Fetal mortality data from Lancaster, Penn., Chicago, Ill. and Minneapolis, Minn. are presented which support the authors' earlier findings in Indiana and Montreal that a positive relationship exists between the degree of liability to malformation and the incidence of fetal deaths in probands' sibships. Altogether, the study involved 189 CL sibships, 690 CLP sibships, and 3,416 pregnancies. On the basis of these data, which are derived from families of several different backgrounds of European ancestry, it is generalized that, as we proceed from CL sibships to CLP sibships, there is a doubling effect on fetal mortality. The consistency of this finding in several population samples is impressive. The implications of this observation are discussed with reference to genetic counseling.

An epidemiological study of facial clefting in Manitoba

The results of an epidemiological survey of facial clefting in the province of Manitoba which covered the years 1964 to 1977, inclusive, are reported. The mean annual incidence of total facial clefts was 2 in 1000 births; the incidence of cleft lip +/- cleft palate (CLP), and of cleft palate (CP), unassociated with a syndrome or two or more major malformations, was 1.05 in 1000 and 0.46 in 1000, respectively. Mennonite infants were over-represented in the CLP group and Amerindian infants in both the CLP and CP groups. These ethnic groups also had more familial cases and showed higher average coefficients of inbreeding. Recurrence rates among sibs were found to be influenced by the presence or absence of additional affected relatives and by the presence of malformations in the proband. It is possible that these latter two variables may not be independent.

Genetics and ageing in man

Among the conflicts of modern life is that faced by many educated women between the desire to pursue a professional career and the demands of their potential maternal role. Some resolve this by deferring having children. This deferment, coupled with an increased awareness of birth defects generally and of the problems faced by older mothers, leads to an increasing number of queries to genetic advisory services, family doctors, obstetricians, and family planning centres, as to the specific risks in reproduction by older parents. The appreciable risk of death in childbed of earlier days is no longer with us, thanks to modern obstetric techniques. But the child morbidity due to congenital and genetic disorders, already appreciable (Roberts, Chavez & Court, 1970; Roberts, 1975) and increasing both proportionately and absolutely, and the evidence that some of these increase in incidence with age, mean that there is a real basis for the enquirers' concern. The following review of the ways in which parental ageing affects the incidence of such disorders, and of the mechanisms that appear to be responsible, places the increased risks in perspective.

The effects of zero population growth on the incidence of cleft lip and palate in Western Australia

A total of 613 cases of cleft lip, cleft palate, and combinations of both (CLP(P)) has been ascertained in the period from 1958 to 1975 in Western Australia. Near-total ascertainment of cases during this period was obtained from multiple sources. There has been a significant decline in the total incidence and the cleft lip and palate (CLP) incidence in males. The hypothesis is presented that these changes are linked to the changing fertility pattern throughout Australia (as technological improvements are made in the simplicity and efficacy of birth control), and abortion (as social attitudes change); and as the birthrate drops towards zero population growth (ZPG). The paper presents two critical observations: (i) the link between CLP(P) incidence, and demographic changes; (ii) in differing behaviour of cleft lip (CL) and CLP, which were previously regarded as linked conditions.

The association of sex ratio anomalies with pyloric stenosis

Published family data were examined for evidence of aberrant sex ratios in relatives of pyloric stenosis index cases. An excess of males over females was found among unaffected members of sibships in which there occurred more than one case of pyloric stenosis. The male excess among affected members of these sibships did not differ from that among index cases without affected sibs. An unusual frequency of spontaneous abortions in these subships, which might account for the observed excess of males, was not observed. No evidence was found of sex ratio anomalies in other classes of relative of pyloric stenosis index cases, whether or not the index cases had affected sibs.

Incidence rates for cleft lip and palate in British Columbia 1952-71 for North American Indian, Japanese, Chinese and total populations: secular trends over twenty years

The incidence of cleft lip and/or cleft palate was examined for the 1952-71 period for the Province of British Columbia. Although there were some fluctuations, some of which were significant, there was no general trend which indicated that the rates were either increasing or decreasing. These rates are important for a background calculation when investigating new invironment teratogens. The total rate of 1.97 per 1,000 live birth is comparable with other Caucasian populations where there is good ascertainment and adequate follow-up period. This study also confirmed the previously reported high rate for North American Indians in British Columbia (3.74 per 1,000 live births) and established rates for the Japanese (3.36 per 1,000 live births) and Chinese (1.76 per 1,000 live births) of British Columbia. Since these three sub-populations are relatively small in relation to the total population, they do not influence the overall total rate to any great extent.

Effects of antenatal exposure to anorectic drugs

In a large prospective, observational study of pregnancy and child development, the anorectic drugs (amphetamines and phenmetrazine) prescribed to gravid women during different stages of pregnancy were evaluated for their teratogenicity. The severe congenital anomaly rate (SCA) per 100 live-born children at age five years did not differ from the SCA rate of the group of children whose mothers did not use these drugs. There was, however, an excess of oral clefts in the offspring of mothers who had amphetamines prescribed in the first 56 days from the last menstrual period. A rought test of efficacy of anorectic drugs by comparing mean weight gains in four-week periods before and after the prescription showed only short-term and limited reduction of weight gain.

Racial variations in the incidence of congenital malformations

Racial variation in the incidence of several common congenital malformations has been studied in Atlanta, Georgia. The white-to-black incidence ratios were substantially different from unity for single defects, while approximate equality of rates was noted for multiple defects. Amongst the specific malformations for which familial data were available, affected first- and second-degree relatives were found only in the families of probands with single defects. It is postulated that these findings may indicate a more prominent function of the environment in the genesis of multiple malformations than is the case for single defects, the occurrence of which may be more strongly affected by non-sporadic genetic factors.