Polymorphisms in the fetal progesterone receptor and a calcium-activated potassium channel isoform are associated with preterm birth in an Argentinian population

OBJECTIVE

To investigate genetic etiologies of preterm birth (PTB) in Argentina through evaluation of single-nucleotide polymorphisms (SNPs) in candidate genes and population genetic admixture.

STUDY DESIGN

Genotyping was performed in 389 families. Maternal, paternal and fetal effects were studied separately. Mitochondrial DNA (mtDNA) was sequenced in 50 males and 50 females. Y-chromosome anthropological markers were evaluated in 50 males.

RESULT

Fetal association with PTB was found in the progesterone receptor (PGR, rs1942836; P=0.004). Maternal association with PTB was found in small conductance calcium activated potassium channel isoform 3 (KCNN3, rs883319; P=0.01). Gestational age associated with PTB in PGR rs1942836 at 32-36 weeks (P=0.0004). MtDNA sequencing determined 88 individuals had Amerindian consistent haplogroups. Two individuals had Amerindian Y-chromosome consistent haplotypes.

CONCLUSION

This study replicates single locus fetal associations with PTB in PGR, maternal association in KCNN3, and demonstrates possible effects for divergent racial admixture on PTB.

Preferential associated anomalies in 818 cases of microtia in South America

The etiology of microtia remains unknown in most cases. The identification of patterns of associated anomalies (i.e., other anomalies that occur with a given congenital anomaly in a higher than expected frequency), is a methodology that has been used for research into the etiology of birth defects. We conducted a study based on cases of microtia that were diagnosed from more than 5 million live (LB)- and stillbirths (SB) examined in hospitals participating in ECLAMC (Latin American Collaborative Study of Congenital Malformations) between 1967 and 2009. We identified 818 LB and SB with microtia and at least one additional non-related major congenital anomaly (cases) and 15,969 LB and SB with two or more unrelated major congenital anomalies except microtia (controls). A logistic regression analysis was performed to identify the congenital anomalies preferentially associated with microtia. Preferential associations were observed for 10 congenital anomalies, most of them in the craniofacial region, including facial asymmetry, choanal atresia, and eyelid colobomata. The analysis by type of microtia showed that for anomalies such as cleft lip and palate, macrostomia, and limb reduction defects, the frequency increased with the severity of the microtia. In contrast, for other anomalies the frequency tended to be the same across all types of microtia. Based on these results we will integrate data on the developmental pathways related to preferentially associated congenital anomalies for future studies investigating the etiology of microtia.

Hormone therapy during pregnancy and isolated hypospadias: an international case-control study

Mothers of boys with hypospadias and control mothers were interviewed in eight malformation monitoring programs around the world. Hormone therapy was used quite frequently in five but rarely in three of the programs. The odds ratio for hypospadias after hormone therapy during pregnancy was 2.8 (95% confidence limits 1.2, 6.9) but there was no correlation between the timing of hormone therapy and the location of the urethral orifice, nor between the severity of the malformation and hormone therapy. Programs with the highest hormone exposure rate showed the lowest odds ratio for pregnancy bleeding, the most common reason for hormone therapy. These latter findings cast doubts on the causal association between hormone therapy and isolated hypospadias. Alternative explanations are recall or interviewer bias or unidentified confounders.

Explaining racial disparities in infant health in Brazil

OBJECTIVES

We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil.

METHODS

We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities.

RESULTS

The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone.

CONCLUSIONS

Public policies to improve children's health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil.

Fine-mapping of 5q12.1-13.3 unveils new genetic contributors to caries

Caries is a multifactorial disease and little is still known about the host genetic factors influencing susceptibility. Our previous genome-wide linkage scan has identified the interval 5q12.1-5q13.3 as linked to low caries susceptibility in Filipino families. Here we fine-mapped this region in order to identify genetic contributors to caries susceptibility. Four hundred and seventy-seven subjects from 72 pedigrees with similar cultural and behavioral habits and limited access to dental care living in the Philippines were studied. DMFT scores and genotype data of 75 single-nucleotide polymorphisms were evaluated in the Filipino families with the Family-Based Association Test. For replication purposes, a total 1,467 independent subjects from five different populations were analyzed in a case-control format. In the Filipino cohort, statistically significant and borderline associations were found between low caries experience and four genes spanning 13 million base pairs (PART1, ZSWIM6, CCNB1, and BTF3). We were able to replicate these results in some of the populations studied. We detected PART1 and BTF3 expression in whole saliva, and the expression of BTF3 was associated with caries experience. Our results suggest BTF3 may have a functional role in protecting against caries.

Does the relationship between prenatal care and birth weight vary by oral clefts? evidence using South American and United States samples

OBJECTIVE

To evaluate if the association between prenatal care use and birth weight (BW) varies for infants with cleft lip and/or cleft palate (CL/P), classified into isolated and non-isolated forms, compared with unaffected infants.

STUDY DESIGN

The study employed 2 datasets. The first included a multi-country sample of 2405 infants with CL/P and 24046 infants without CL/P born in 1996-2007 in South America. The second was a sample of 2122 infants with CL/P and 297415 without CL/P from the United States 2004 natality dataset. Separate analyses were performed for the South American and United States samples. The association between prenatal care and BW was evaluated separately for isolated CL/P, non-isolated CL/P, and unaffected infants using regression models adjusting for several background characteristics.

RESULTS

Prenatal care was associated with improved BW for all infant groups, with greater BW increases for infants with CL/P particularly non-isolated forms. In the South American sample, BW increased by 108, 69, and 40 g on average per prenatal visit for infants with non-isolated CL/P, infants with isolated CL/P, and unaffected infants, respectively. In the United States sample, BW increased by 51, 21, and 16 g on average per prenatal visit for these infant groups, respectively.

CONCLUSIONS

Prenatal care was associated with larger BW increases for pregnancies complicated with CL/P, particularly non-isolated forms, compared with unaffected pregnancies. Given that reduced BW is a well-recognized comorbidity of CL/P, the findings highlight the importance of prenatal care for at-risk pregnancies as a tertiary-prevention intervention to reduce the health burden of CL/P.

Methodological approaches to evaluate teratogenic risk using birth defect registries: advantages and disadvantages

Background

Different approaches have been used in case-control studies to estimate maternal exposure to medications and the risk of birth defects. However, the performance of these approaches and how they affect the odds ratio (OR) estimates have not been evaluated using birth-defect surveillance programmes. The aim of this study was to evaluate the scope and limitations of three case-control approaches to assess the teratogenic risk of birth defects in mothers exposed to antiepileptic medications, insulin, or acetaminophen.

Methodology/Principal Findings

We studied 110,814 non-malformed newborns and 58,514 live newborns with birth defects registered by the Latin American Collaborative Study of Congenital Anomalies (ECLAMC) between 1967 and 2008. Four controls were randomly selected for each case in the same hospital and period, and three different control groups were used: non-malformed newborns (HEALTHY), malformed newborns (SICK), and a subgroup of SICK, only-exposed cases (OECA). Associations were evaluated using OR and Pearson's chi-square (P<0.01). There were no concordance correlations between the HEALTHY and OECA designs, and the average OR differences ranged from 3.0 to 11.5 for the three evaluated medicines. The overestimations observed for HEALTHY design were increased as higher OR values were given, with a high and statistically significant correlation between the difference and the mean. On the contrary, the concordance correlations obtained between the SICK and OECA designs were quite good, with no significant differences in the average risks.

Conclusions

The HEALTHY design estimates the true population OR, but shows a high rate of false-positive results presumably caused by differential misclassification bias. This bias decreases with the increase of the proportion of exposed controls. SICK and OECA odds ratios cannot be considered a direct estimate of the true population OR except under certain conditions. However, the SICK and OECA designs could provide practical information to generate hypotheses about potential teratogens.

Enamel formation genes influence enamel microhardness before and after cariogenic challenge

There is evidence for a genetic component in caries susceptibility, and studies in humans have suggested that variation in enamel formation genes may contribute to caries. For the present study, we used DNA samples collected from 1,831 individuals from various population data sets. Single nucleotide polymorphism markers were genotyped in selected genes (ameloblastin, amelogenin, enamelin, tuftelin, and tuftelin interacting protein 11) that influence enamel formation. Allele and genotype frequencies were compared between groups with distinct caries experience. Associations with caries experience can be detected but they are not necessarily replicated in all population groups and the most expressive results was for a marker in AMELX (p=0.0007). To help interpret these results, we evaluated if enamel microhardness changes under simulated cariogenic challenges are associated with genetic variations in these same genes. After creating an artificial caries lesion, associations could be seen between genetic variation in TUFT1 (p=0.006) and TUIP11 (p=0.0006) with enamel microhardness. Our results suggest that the influence of genetic variation of enamel formation genes may influence the dynamic interactions between the enamel surface and the oral cavity.

Interaction between IRF6 and TGFA genes contribute to the risk of nonsyndromic cleft lip/palate

Previous evidence from tooth agenesis studies suggested IRF6 and TGFA interact. Since tooth agenesis is commonly found in individuals with cleft lip/palate (CL/P), we used four large cohorts to evaluate if IRF6 and TGFA interaction contributes to CL/P. Markers within and flanking IRF6 and TGFA genes were tested using Taqman or SYBR green chemistries for case-control analyses in 1,000 Brazilian individuals. We looked for evidence of gene-gene interaction between IRF6 and TGFA by testing if markers associated with CL/P were overtransmitted together in the case-control Brazilian dataset and in the additional family datasets. Genotypes for an additional 142 case-parent trios from South America drawn from the Latin American Collaborative Study of Congenital Malformations (ECLAMC), 154 cases from Latvia, and 8,717 individuals from several cohorts were available for replication of tests for interaction. Tgfa and Irf6 expression at critical stages during palatogenesis was analyzed in wild type and Irf6 knockout mice. Markers in and near IRF6 and TGFA were associated with CL/P in the Brazilian cohort (p<10⁻⁶). IRF6 was also associated with cleft palate (CP) with impaction of permanent teeth (p<10⁻⁶). Statistical evidence of interaction between IRF6 and TGFA was found in all data sets (p = 0.013 for Brazilians; p = 0.046 for ECLAMC; p = 10⁻⁶ for Latvians, and p = 0.003 for the 8,717 individuals). Tgfa was not expressed in the palatal tissues of Irf6 knockout mice. IRF6 and TGFA contribute to subsets of CL/P with specific dental anomalies. Moreover, this potential IRF6-TGFA interaction may account for as much as 1% to 10% of CL/P cases. The Irf6-knockout model further supports the evidence of IRF6-TGFA interaction found in humans.

Prevalence of esophageal atresia among 18 international birth defects surveillance programs

BACKGROUND

The prevalence of esophageal atresia (EA) has been shown to vary across different geographical settings. Investigation of geographical differences may provide an insight into the underlying etiology of EA.

METHODS

The study population comprised infants diagnosed with EA during 1998 to 2007 from 18 of the 46 birth defects surveillance programs, members of the International Clearinghouse for Birth Defects Surveillance and Research. Total prevalence per 10,000 births for EA was defined as the total number of cases in live births, stillbirths, and elective termination of pregnancy for fetal anomaly (ETOPFA) divided by the total number of all births in the population.

RESULTS

Among the participating programs, a total of 2943 cases of EA were diagnosed with an average prevalence of 2.44 (95% confidence interval [CI], 2.35-2.53) per 10,000 births, ranging between 1.77 and 3.68 per 10,000 births. Of all infants diagnosed with EA, 2761 (93.8%) were live births, 82 (2.8%) stillbirths, 89 (3.0%) ETOPFA, and 11 (0.4%) had unknown outcomes. The majority of cases (2020, 68.6%), had a reported EA with fistula, 749 (25.5%) were without fistula, and 174 (5.9%) were registered with an unspecified code.

CONCLUSIONS

On average, EA affected 1 in 4099 births (95% CI, 1 in 3954-4251 births) with prevalence varying across different geographical settings, but relatively consistent over time and comparable between surveillance programs. Findings suggest that differences in the prevalence observed among programs are likely to be attributable to variability in population ethnic compositions or issues in reporting or registration procedures of EA, rather than a real risk occurrence difference. Birth Defects Research (Part A), 2012.

Hospital volume and mortality of very low-birthweight infants in South America

OBJECTIVE

To assess the effects of hospital volume of very low-birthweight (VLBW) infants on in-hospital mortality of VLBW and very preterm birth (VPB) infants in South America.

DATA SOURCES/STUDY SETTING

Birth-registry data for infants born in 1982-2008 at VLBW or very preterm in 66 hospitals in Argentina, Brazil, and Chile.

DESIGN

Regression analyses that adjust for several individual-level demographic, socioeconomic, and health factors; hospital-level characteristics; and country-fixed effects are employed.

DATA COLLECTION/EXTRACTION METHODS

Physicians interviewed mothers before hospital discharge and abstracted hospital medical records using similar methods at all hospitals.

PRINCIPAL FINDINGS

Volume has significant nonlinear beneficial effects on VLBW and VPB in-hospital survival. The largest survival benefits--more than 80 percent decrease in mortality rates--are with volume increases from low to medium or medium-high levels (from ≤ 25 to 72 infants annually) with significantly lower incremental benefits thereafter. The cumulative volume effects are maximized at the 121-144 annual VLBW infant range--about 90 percent decrease in mortality rates compared to <25 VLBW infants annually.

CONCLUSIONS

Increasing the access of pregnancies at-risk of VLBW and VPB to medium- or high-volume hospitals up to 144 VLBW infants per year may substantially improve in-hospital infant survival in the study countries.

Application of neurodevelopmental screening to a sample of South American infants: the Bayley Infant Neurodevelopmental Screener (BINS)

OBJECTIVE

To evaluate the utility of the Bayley Infant Neurodevelopmental Screener (BINS), standardized in the US, for South American infants, 3-24 months of age.

METHODS

Thirty-five physicians administered the BINS to 2471 South American infants recruited during routine well-child visits, 578 (23%) from Brazil and 1893 (77%) from six other South American countries. The BINS was translated into Spanish and Portuguese and participating physicians were trained to administer the BINS. Physician inter-rater agreement with training tapes was 84.4%; test-retest reliability for age item sets ranged from 0.80 to 0.93 (Pearson's r). Infants were classified into being at low, moderate, or high risk for developmental delay or neurological impairment based on their total BINS score. The sample was stratified by infant's age, sex and language (Spanish and Portuguese). The BINS scores were compared to the scores of the US infant sample used to standardize the BINS.

RESULTS

Female infants performed higher than male at 16-20 months and 21-24 months; male infant scores were more variable at 5-6 months. Scores on only two items were significantly different between Spanish and Portuguese speaking participants. South American scores were typically significantly higher than the US sample, and a lower proportion of infants were classified as being at high risk in the South American sample than in the US standardization sample.

CONCLUSION

Overall, the results of this study indicate that the BINS is feasible and appropriate for neurodevelopmental screening in South America. Further studies are needed to confirm the BINS utility in South America, including its use with a clinical sample.

Association of AXIN2 with non-syndromic oral clefts in multiple populations

We have previously shown the association of AXIN2 with oral clefts in a US population. Here, we expanded our study to explore the association of 11 AXIN2 markers in 682 cleft families from multiple populations. Alleles for each AXIN2 marker were tested for transmission distortion with clefts by means of the Family-based Association Test. We observed an association with SNP rs7224837 and all clefts in the combined populations (p = 0.001), and with SNP rs3923086 and cleft lip and palate in Asian populations (p = 0.004). We confirmed our association findings in an additional 528 cleft families from the United States (p < 0.009). We tested for gene-gene interaction between AXIN2 and additional cleft susceptibility loci. We assessed and detected Axin2 mRNA and protein expression during murine palatogenesis. In addition, we also observed co-localization of Axin2 with Irf6 proteins, particularly in the epithelium. Our results continue to support a role for AXIN2 in the etiology of human clefting. Additional studies should be performed to improve our understanding of the biological mechanisms linking AXIN2 to oral clefts.

The effect of systematic pediatric care on neonatal mortality and hospitalizations of infants born with oral clefts

Background

Cleft lip and/or palate (CL/P) increase mortality and morbidity risks for affected infants especially in less developed countries. This study aimed at assessing the effects of systematic pediatric care on neonatal mortality and hospitalizations of infants with cleft lip and/or palate (CL/P) in South America.

Methods

The intervention group included live-born infants with isolated or associated CL/P in 47 hospitals between 2003 and 2005. The control group included live-born infants with CL/P between 2001 and 2002 in the same hospitals. The intervention group received systematic pediatric care between the 7^th and 28^th day of life. The primary outcomes were mortality between the 7^th and 28^th day of life and hospitalization days in this period among survivors adjusted for relevant baseline covariates.

Results

There were no significant mortality differences between the intervention and control groups. However, surviving infants with associated CL/P in the intervention group had fewer hospitalization days by about six days compared to the associated control group.

Conclusions

Early systematic pediatric care may significantly reduce neonatal hospitalizations of infants with CL/P and additional birth defects in South America. Given the large healthcare and financial burden of CL/P on affected families and the relatively low cost of systematic pediatric care, improving access to such care may be a cost-effective public policy intervention.

Trial Registration

ClinicalTrials.gov: NCT00097149

Phocomelia: a worldwide descriptive epidemiologic study in a large series of cases from the International Clearinghouse for Birth Defects Surveillance and Research, and overview of the literature

Epidemiologic data on phocomelia are scarce. This study presents an epidemiologic analysis of the largest series of phocomelia cases known to date. Data were provided by 19 birth defect surveillance programs, all members of the International Clearinghouse for Birth Defects Surveillance and Research. Depending on the program, data corresponded to a period from 1968 through 2006. A total of 22,740,933 live births, stillbirths and, for some programs, elective terminations of pregnancy for fetal anomaly (ETOPFA) were monitored. After a detailed review of clinical data, only true phocomelia cases were included. Descriptive data are presented and additional analyses compared isolated cases with those with multiple congenital anomalies (MCA), excluding syndromes. We also briefly compared congenital anomalies associated with nonsyndromic phocomelia with those presented with amelia, another rare severe congenital limb defect. A total of 141 phocomelia cases registered gave an overall total prevalence of 0.62 per 100,000 births (95% confidence interval: 0.52-0.73). Three programs (Australia Victoria, South America ECLAMC, Italy North East) had significantly different prevalence estimates. Most cases (53.2%) had isolated phocomelia, while 9.9% had syndromes. Most nonsyndromic cases were monomelic (55.9%), with an excess of left (64.9%) and upper limb (64.9%) involvement. Most nonsyndromic cases (66.9%) were live births; most isolated cases (57.9%) weighed more than 2,499 g; most MCA (60.7%) weighed less than 2,500 g, and were more likely stillbirths (30.8%) or ETOPFA (15.4%) than isolated cases. The most common associated defects were musculoskeletal, cardiac, and intestinal. Epidemiological differences between phocomelia and amelia highlighted possible differences in their causes.

Cyclopia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research

Cyclopia is characterized by the presence of a single eye, with varying degrees of doubling of the intrinsic ocular structures, located in the middle of the face. It is the severest facial expression of the holoprosencephaly (HPE) spectrum. This study describes the prevalence, associated malformations, and maternal characteristics among cases with cyclopia. Data originated in 20 Clearinghouse (ICBDSR) affiliated birth defect surveillance systems, reported according to a single pre-established protocol. A total of 257 infants with cyclopia were identified. Overall prevalence was 1 in 100,000 births (95%CI: 0.89-1.14), with only one program being out of range. Across sites, there was no correlation between cyclopia prevalence and number of births (r = 0.08; P = 0.75) or proportion of elective termination of pregnancy (r = -0.01; P = 0.97). The higher prevalence of cyclopia among older mothers (older than 34) was not statistically significant. The majority of cases were liveborn (122/200; 61%) and females predominated (male/total: 42%). A substantial proportion of cyclopias (31%) were caused by chromosomal anomalies, mainly trisomy 13. Another 31% of the cases of cyclopias were associated with defects not typically related to HPE, with more hydrocephalus, heterotaxia defects, neural tube defects, and preaxial reduction defects than the chromosomal group, suggesting the presence of ciliopathies or other unrecognized syndromes. Cyclopia is a very rare defect without much variability in prevalence by geographic location. The heterogeneous etiology with a high prevalence of chromosomal abnormalities, and female predominance in HPE, were confirmed, but no effect of increased maternal age or association with twinning was observed.

Very rare defects: what can we learn?

The International Clearinghouse for Birth Defects Surveillance and Research conducted a study on very rare defects (VRDs) to test methodologies in their population surveillance and to increase the knowledge of their epidemiology. Eight VRDs: acardia (AC), amelia (AM), bladder exstrophy (BE), cloaca exstrophy (CE), conjoined twins (CT), cyclopia (CY), "true" phocomelia (PH), and sirenomelia (SI) were selected, all of whom showed prevalences in the order of 1/100,000 births, except for BE: 1/48,000 births. Materials in this investigation from 25 million pregnancy outcomes, were provided by 22 Clearinghouse-member programs. The study protocol provided a working definition, a summary of the phenotypic characteristic, and a list of ICD-9 and ICD-10 codes for each VRDs. Learned lessons include: (1) The suspected associations of decreasing risk with advancing maternal age in AM and SI, and increasing risk in BE, and increasing frequency of twins in SI, were confirmed. (2) Morphologically similar defects showed dissimilar epidemiological characteristics, namely, AM and PH, and BE and CE. (3) Heterogeneity in total prevalences for most VRDs among different surveillance programs were attributed to operational reasons, except for SI and CT in which Amerindian ethnicity seems to be associated with higher prevalence. (4) Verbatim description is essential and must be stored in electronic files. In addition to codes. (5) Dysmorphologists or clinical geneticists are an essential part of the coordinating team of the surveillance program. (6) ICD coding system is insufficient. (7) Surveillance programs should be a valuable source of information on exposures to risk factors during pregnancy.

Sirenomelia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research, and literature review

Sirenomelia is a very rare limb anomaly in which the normally paired lower limbs are replaced by a single midline limb. This study describes the prevalence, associated malformations, and maternal characteristics among cases with sirenomelia. Data originated from 19 birth defect surveillance system members of the International Clearinghouse for Birth Defects Surveillance and Research, and were reported according to a single pre-established protocol. Cases were clinically evaluated locally and reviewed centrally. A total of 249 cases with sirenomelia were identified among 25,290,172 births, for a prevalence of 0.98 per 100,000, with higher prevalence in the Mexican registry. An increase of sirenomelia prevalence with maternal age less than 20 years was statistically significant. The proportion of twinning was 9%, higher than the 1% expected. Sex was ambiguous in 47% of cases, and no different from expectation in the rest. The proportion of cases born alive, premature, and weighting less than 2,500 g were 47%, 71.2%, and 88.2%, respectively. Half of the cases with sirenomelia also presented with genital, large bowel, and urinary defects. About 10-15% of the cases had lower spinal column defects, single or anomalous umbilical artery, upper limb, cardiac, and central nervous system defects. There was a greater than expected association of sirenomelia with other very rare defects such as bladder exstrophy, cyclopia/holoprosencephaly, and acardia-acephalus. The application of the new biological network analysis approach, including molecular results, to these associated very rare diseases is suggested for future studies.

Amelia: a multi-center descriptive epidemiologic study in a large dataset from the International Clearinghouse for Birth Defects Surveillance and Research, and overview of the literature

This study describes the epidemiology of congenital amelia (absence of limb/s), using the largest series of cases known to date. Data were gathered by 20 surveillance programs on congenital anomalies, all International Clearinghouse for Birth Defects Surveillance and Research members, from all continents but Africa, from 1968 to 2006, depending on the program. Reported clinical information on cases was thoroughly reviewed to identify those strictly meeting the definition of amelia. Those with amniotic bands or limb-body wall complex were excluded. The primary epidemiological analyses focused on isolated cases and those with multiple congenital anomalies (MCA). A total of 326 amelia cases were ascertained among 23,110,591 live births, stillbirths and (for some programs) elective terminations of pregnancy for fetal anomalies. The overall total prevalence was 1.41 per 100,000 (95% confidence interval: 1.26-1.57). Only China Beijing and Mexico RYVEMCE had total prevalences, which were significantly higher than this overall total prevalence. Some under-registration could influence the total prevalence in some programs. Liveborn cases represented 54.6% of total. Among monomelic cases (representing 65.2% of nonsyndromic amelia cases), both sides were equally involved, and the upper limbs (53.9%) were slightly more frequently affected. One of the most interesting findings was a higher prevalence of amelia among offspring of mothers younger than 20 years. Sixty-nine percent of the cases had MCA or syndromes. The most frequent defects associated with amelia were other types of musculoskeletal defects, intestinal, some renal and genital defects, oral clefts, defects of cardiac septa, and anencephaly.

Cloacal exstrophy: an epidemiologic study from the International Clearinghouse for Birth Defects Surveillance and Research

Cloacal exstrophy presents as a complex abdominal wall defect thought to result from a mesodermal abnormality. Anatomically, its main components are Omphalocele, bladder Exstrophy and Imperforate anus. Other associated malformations include renal malformations and Spine defects (OEIS complex). Historically, the prevalence ranges from 1 in 200,000 to 400,000 births, with higher rates in females. Cloacal exstrophy is likely etiologically heterogeneous as suggested by its recurrence in families and occurrence in monozygotic twins. The defect has been described in infants with limb-body wall, with trisomy 18, and in one pregnancy exposed to Dilantin and diazepam. Due to its rarity, the use of a nonspecific diagnostic code for case identification, and lack of validation of the clinical findings, cloacal exstrophy remains an epidemiologic challenge. The purpose of this study was to describe the prevalence, associated anomalies and maternal characteristics among infants born with cloacal exstrophy. We used data from the International Clearinghouse for Birth Defects Surveillance and Research submitted from 18 birth defect surveillance programs representing 24 countries. Cases were clinically evaluated locally and reviewed centrally by two authors. Cases of persistent cloaca were excluded. A total of 186 cases of cloacal exstrophy were identified. Overall prevalence was 1 in 131,579 births: ranging from 1 in 44,444 births in Wales to 1 in 269,464 births in South America. Live birth prevalence was 1 in 184,195 births. Prevalence ratios did not vary by maternal age. Forty-two (22.6%) cases met the criteria for the OEIS complex, whereas 60 (32.3%) were classified as OEI and 18 (9.7%) as EIS (one with suspected VATER (0.5%)). Other findings included two cases with trisomy 13 (one without a karyotype confirmation), one with mosaic trisomy 12 (0.5%), one with mosaic 45,X (0.5%) and one classified as having amnion band sequence (0.5%). Twenty-seven (14.5%) infants had other anomalies unrelated to cloacal exstrophy. Cloacal exstrophy is a rare anomaly with variability in prevalence by geographic location. The proportion of cases classified as OEIS complex was lower in this study than previously reported. Among all cases, 54.8% were reported to have an omphalocele.

Bladder exstrophy: an epidemiologic study from the International Clearinghouse for Birth Defects Surveillance and Research, and an overview of the literature

Bladder exstrophy (BE) is a complex congenital anomaly characterized by a defect in the closure of the lower abdominal wall and bladder. We aimed to provide an overview of the literature and conduct an epidemiologic study to describe the prevalence, and maternal and case characteristics of BE. We used data from 22 participating member programs of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). All cases were reviewed and classified as isolated, syndrome, and multiple congenital anomalies. We estimated the total prevalence of BE and calculated the frequency and odds ratios for various maternal and case characteristics. A total of 546 cases with BE were identified among 26,355,094 births. The total prevalence of BE was 2.07 per 100,000 births (95% CI: 1.90-2.25) and varied between 0.52 and 4.63 among surveillance programs participating in the study. BE was nearly twice as common among male as among female cases. The proportion of isolated cases was 71%. Prevalence appeared to increase with increasing categories of maternal age, particularly among isolated cases. The total prevalence of BE showed some variations by geographical region, which is most likely attributable to differences in registration of cases. The higher total prevalence among male cases and older mothers, especially among isolated cases, warrants further attention.

Sentinel phenotype for rubella embryopathy: time-space distribution in Brazil

The dyad comprising eye anomalies and congenital heart defects in the same newborn has been proposed as the best sentinel phenotype for the early detection of rubella embryopathy. Time-space birth prevalence distributions of the eye-heart dyad were described in 36 Brazilian hospitals from the Latin-American Collaborative Study of Congenital Anomalies - ECLAMC network, for the period 1994-2008. Seventy dyad cases observed among 554,531 births showed seasonal variation (Χ2 = 5.84; p < 0.05), suggesting an environmental etiology, with an increase in cases in October-March and acrophase in December. The secular distribution of dyad prevalence rates was consistent with the distribution of rubella cases in Brazil, showing a decrease from 1994 to 2004, followed by an increase until 2008. Two geographic clusters were identified, one with high and the other with low dyad prevalence. In the high prevalence cluster, a secular increase was observed, starting in 1999, matching the rubella epidemic waves observed in Brazil in 1998-2000 and 2006.

Epidemiological surveillance of birth defects compatible with thalidomide embryopathy in Brazil

The thalidomide tragedy of the 1960s resulted in thousands of children being born with severe limb reduction defects (LRD), among other malformations. In Brazil, there are still babies born with thalidomide embryopathy (TE) because of leprosy prevalence, availability of thalidomide, and deficiencies in the control of drug dispensation. Our objective was to implement a system of proactive surveillance to identify birth defects compatible with TE. Along one year, newborns with LRD were assessed in the Brazilian hospitals participating in the Latin-American Collaborative Study of Congenital Malformations (ECLAMC). A phenotype of LRD called thalidomide embryopathy phenotype (TEP) was established for surveillance. Children with TEP born between the years 2000–2008 were monitored, and during the 2007–2008 period we clinically investigated in greater detail all cases with TEP (proactive period). The period from 1982 to 1999 was defined as the baseline period for the cumulative sum statistics. The frequency of TEP during the surveillance period, at 3.10/10,000 births (CI 95%: 2.50–3.70), was significantly higher than that observed in the baseline period (1.92/10,000 births; CI 95%: 1.60–2.20), and not uniformly distributed across different Brazilian regions. During the proactive surveillance (2007–2008), two cases of suspected TE were identified, although the two mothers had denied the use of the drug during pregnancy. Our results suggest that TEP has probably increased in recent years, which coincides with the period of greater thalidomide availability. Our proactive surveillance identified two newborns with suspected TE, proving to be a sensitive tool to detect TE. The high frequency of leprosy and the large use of thalidomide reinforce the need for a continuous monitoring of TEP across Brazil.

Associated anomalies among infants with oral clefts at birth and during a 1-year follow-up

Reports of birth defects rates may focus on defects observed in the newborn period or include defects diagnosed at older ages. However, little information is available on the rates of additional anomalies detected after birth or on the ages at which such anomalies are diagnosed. The aims of this work were to describe the initial diagnoses of oral clefts, isolated or associated with other defects, in newborn infants ascertained in hospitals of the ECLAMC network, and diagnostic changes that occurred due to detection of additional defects during a 1-year follow-up period. Seven hundred ten liveborn infants with cleft lip only (CLO), cleft lip with cleft palate (CLP), or cleft palate (CP) were ascertained between 2003 and 2005. Prevalence estimates of isolated and associated (ASO) clefts, diagnoses in infants with associated clefts, and the percentage of isolated clefts that were reclassified as associated were established. Birth prevalence estimates (per 1,000) were as follows: Total: 1.7; CLP: 0.94 (ASO = 23.5%); CP: 0.46 (ASO = 42.3%); CLO: 0.28 (ASO = 7.6%). Initial diagnoses in infants with associated clefts included 38 infants with chromosomal abnormalities, 33 with non-chromosomal syndromes, 16 with malformation sequences, and 98 with multiple anomalies of unknown etiology. Seven percent of newborns initially classified as isolated were later reclassified as associated. Ten infants without associated defects or clinically suspected syndromes were diagnosed as syndromic only through laboratory findings or family history, illustrating the difference between the terms associated versus isolated, which refers to presence or absence of associated anomalies, and syndromic versus non-syndromic, which refers to etiology.