Iêda M. Orioli

ECLAMC: The Latin-American Collaborative Study of Congenital Malformations

Definition: ECLAMC (‘Estudio Colaborativo Latino Americano de Malformaciones Congénitas’) is a program for the clinical and epidemiological investigation of risk factors in the etiology of congenital anomalies in Latin-American hospitals, using a case-control methodological approach. It is a voluntary agreement among professionals lacking institutional base as well as designated budgets. ECLAMC has been usually funded by research-funding agencies rather than public health ministries. The National Research Councils of Argentina and Brazil have been the main sources of support during its 36 years of existence. Since vital and health statistics are unreliable in South America, ECLAMC collects all the information required for the denominators in a hospital-based sample of births. ECLAMC can be defined as a continental network of persons interested in research and prevention of birth defects. History and Evolution: From the institutional point of view, ECLAMC has had headquarters in diverse centers of Argentina and Brazil, but always as an independent research project, without a defined administrative link. ECLAMC began operating in 1967, as an investigation limited to the city of Buenos Aires, Argentina, and it gradually expanded until covering all the 10 countries of South America as well as Costa Rica and the Dominican Republic. Even though ECLAMC has maintained essentially the same original experimental design since 1967, due to the data accumulated by the program, the increasing experience as well as the development in science, technical modifications occurred including a DNA bank and a fully informatized data handling system. Since 1974 ECLAMC has been a founder member of the International Clearinghouse for Birth Defects Monitoring Systems; since 1994 a WHO Collaborating Center for the Prevention of Congenital Malformations, and since 2000 a collaborating member of the NIH Global Netwok for Women’s and Children’s Health Research. Methodology: The maternity hospital network of ECLAMC examines around 200,000 births per year. All major and minor anomalies diagnosed at birth in infants weighing 500 g or more are registered according to a manual of procedures. The next non-malformed baby of the same sex born in the same hospital is selected as a control subject for each case. Thus, a one-to-one healthy control group matched by sex, time and place of birth is obtained. As a system of epidemic surveillance, ECLAMC systematically observes the fluctuations in the frequencies of different malformations and, in the case of an alarm for a probable epidemic of a given malformation, at a given moment, and given area, it acts to identify its cause. As termination of pregnancy has severe legal restrictions in South America, prevention of birth defects should concentrate on primary, preconceptional and tertiary measures. Tertiary measures aim to avoid complications of the affected patients from the medical, psychological, and social standpoints.

Reduction of birth prevalence rates of neural tube defects after folic acid fortification in Chile

To verify whether the decreasing neural tube defects birth prevalence rates in Chile are due to folic acid fortification or to pre‐existing decreasing trends, we performed a population survey using a network of Estudio Colaborativo Latino Americano de Malformaciones Congénitas (ECLAMC, Latin American Collaborative Study of Congenital Malformations) maternity hospitals in Chile, between the years 1982 and 2002. Within each maternity hospital, birth prevalence rates of spina bifida and anencephaly were calculated from two pre‐fortification periods (1982–1989 and 1990–2000), and from one fortified period (2001–2002). There was no historical trend for spina bifida birth prevalence rates before folic acid fortification, and there was a 51% (minimum 27%, maximum 66%) decrease in the birth prevalence rates of this anomaly in the fortified period. The relative risks of spina bifida were homogeneous among hospitals in the two period comparisons. There was no historical trend for the birth prevalence of anencephaly comparing the two pre‐fortified periods, but the relative risks were heterogeneous among hospitals in this comparison. There was a 42% (minimum 10%, maximum 63%) decrease in the birth prevalence rate of anencephaly in the fortified period as compared with the immediately pre‐fortified period, with homogeneous relative risks among hospitals. Within the methodological constraints of this study we conclude that the birth prevalence rates for both spina bifida and anencephaly decreased as a result of folic acid fortification, without interference of decreasing secular trends.

Preliminary Data on Changes in Neural Tube Defect Prevalence Rates After Folic Acid Fortification in South America

Several South American countries are fortifying wheat flour with folic acid. However, only Chile started in 2000 to add 2.2 mg/kg, providing 360 μg daily per capita, an acceptable dosage for preventing the occurrence of some neural tube defect (NTD) cases. ECLAMC (Spanish acronym for the Latin American Collaborative Study of Congenital Malformations) routinely monitoring birth defects in South America since 1976, surveyed the impact of this fortification. Data from 361,374 births occurred in 43 South American hospitals, distributed in five different countries, active throughout the 1999–2001 triennium, were selected from the ECLAMC network. Birth prevalence rates for three different congenital anomalies with similar expected prevalence rates, were surveyed by the Cumulative Sum Method (CUSUM) method. They were NTD, oral clefts (OC), and Down syndrome (DS). Expected values were derived from observations made in 1999, and CUSUM was applied to the consecutive series of 24 months covering years 2000 and 2001. Only one of three congenital anomaly types, NTDs, in only one of five sampled out countries, Chile, showed a significant decrease, of 31%, during the 2000–2001 biennium, corresponding to the birth of the periconceptionally fortified infants. The level of significance (P < 0.001) was reached in the 20th month after fortification started, corresponding to August 2001. This is the first observation of a significant decrease in the occurrence of NTD after folic acid food fortification in a population little influenced by confounders common in the developed world as pre‐existing secular decreasing trends, and partially unregistered induced abortions.

Epidemiological assessment of misoprostol teratogenicity

Objective To verify if any of the 15 congenital defects already reported in association with misoprostol can be found within an epidemiological registry of congenital defects.

MSX1 and TGFB3 Contribute to Clefting in South America

MSX1 and TGFB3 have been proposed as genes in which mutations may contribute to non-syndromic forms of oral clefts; however, an interaction between these genes has not been described. The present study attempts to detect transmission distortion of MSX1 and TGFB3 in 217 South American children from their respective mothers. With transmission disequilibrium test analysis, cleft lip with/without cleft palate, cleft lip with palate plus cleft palate only, and all datasets combined showed evidence of association with MSX1 (p = 0.004, p = 0.037, and p = 0.001, respectively). With likelihood ratio test analysis, “cleft lip only” showed association with MSX1 (p = 0.04) and “cleft palate only” with TGFB3 (p = 0.02). A joint analysis of MSX1 and TGFB3 suggested that there may be an interaction between these two loci to increase cleft susceptibility. These results suggest that MSX1 and TGFB3 mutations make a contribution to clefts in South American populations.

Gastroschisis: International epidemiology and public health perspectives

Gastroschisis offers the intriguing epidemiological situation of a pandemic, strongly associated with very low maternal age. Identifying gastroschisis, and distinguishing it from the other abdominal wall defects, is theoretically easy but difficult in practice. The baseline birth prevalence of gastroschisis before the pandemic was approximately 1 in 50,000 births and has increased since between 10‐ and 20‐fold. In many populations worldwide, it is still increasing. Such increasing prevalence and the association with very low maternal age are well proven, but the interaction between these two findings remains unknown. Geographic gradients (decreasing prevalence from North to South) are clear in Continental Europe and suggestive in Britain and Ireland. Gastroschisis seems more frequent in Caucasians compared to African Blacks and Orientals, and in Northern compared to Southern Europeans. These observations indicate the need for investigating gene–environment interactions. Since the global human situation is marked by inequalities among as well as within countries, the medical care and public health impact of gastroschisis varies widely among regions and social strata. The postnatal benefits of prenatal diagnosis of gastroschisis include family awareness; adequate planning of delivery with alerted obstetrical, pediatric, and surgical staff; optimal risk categorization, and personalized protocol for action. The increasing prevalence of gastroschisis combined with improved medical techniques to reduce morbidity and mortality are also increasing the burden and costs of this anomaly on health systems.

Folic acid flour fortification: Impact on the frequencies of 52 congenital anomaly types in three South American countries

The aim of the present investigation was to search for a reduction in birth prevalence estimates of 52 selected types of congenital anomalies, associated with folic acid fortification programs in Chile, Argentina, and Brazil. The material included 3,347,559 total births in 77 hospitals of the three countries during the 1982–2007 period: 596,704 births (17 hospitals) in Chile, 1,643,341 (41 hospitals) in Argentina, and 1,107,514 (19 hospitals) in Brazil. We compared pre‐ and post‐fortification rates within each hospital and the resulting Prevalence Rate Ratios (PRRs) were pooled by country. Statistically significant reductions in birth prevalence estimates after fortification were observed for neural tube defects (NTDs), septal heart defects, transverse limb deficiencies, and subluxation of the hip. However, only the reduction of NTDs appeared to be associated with folic acid fortification and not due to other factors, because of its consistency among the three countries, as well as with previously published reports, and its strong statistical significance. Among the NTDs, the maximum prevalence reduction was observed for isolated cephalic (cervical‐thoracic) spina bifida, followed by caudal (lumbo‐sacral) spina bifida, anencephaly, and cephalocele. This observation suggests etiologic and pathogenetic heterogeneity among different levels of spina bifida, as well as among different NTD subtypes. We concluded that food fortification with folic acid prevents NTDs but not other types of congenital anomalies.

PVRL1 variants contribute to non-syndromic cleft lip and palate in multiple populations

Poliovirus Receptor Like‐1 (PVRL1) is a member of the immunoglobulin super family that acts in the initiation and maintenance of epithelial adherens junctions and is mutated in the cleft lip and palate/ectodermal dysplasia 1 syndrome (CLPED1, OMIM #225000). In addition, a common non‐sense mutation in PVRL1 was discovered more often among non‐syndromic sporadic clefting cases in Northern Venezuela in a previous case‐control study. The present work sought to ascertain the role of PVRL1 in the sporadic forms of orofacial clefting in multiple populations. Multiple rare and common variants from all three splice isoforms were initially ascertained by sequencing 92 Iowan and 86 Filipino cases and CEPH controls. Using a family‐based analysis to examine these variants, the common glycine allele of the G361V coding variant was significantly overtransmitted among all orofacial clefting phenotypes (P = 0.005). This represented G361V genotyping from over 800 Iowan, Danish, and Filipino families. Among four rare amino acid changes found within the V1 and C1 domains, S112T and T131A were found adjacent to critical amino acid positions within the V1 variable domain, regions previously shown to mediate cell‐to‐cell and cell‐to‐virus adhesion. The T131A variant was not found in over 1,300 non‐affected control samples although the alanine is found in other species. The serine of the S112T variant position is conserved across all known PVRL1 sequences. Together these data suggest that both rare and common mutations within PVRL1 make a minor contribution to disrupting the initiation and regulation of cell‐to‐cell adhesion and downstream morphogenesis of the embryonic face.

Clinical and epidemiological studies of amniotic deformity, adhesion, and mutilation (ADAM) sequence in a South American (ECLAMC) population.

Amniotic deformity, adhesion, and mutilation (ADAM) sequence is a heterogeneous condition, with a broad spectrum of anomalies, where intrinsic causes, as defect of germ plasm, vascular disruption, and disturbance of threshold boundaries of morphogens during early gastrulation, alternate with extrinsic causes as amniotic band rupture to explain the condition. This study aimed to identify which phenotypes could be considered as ADAM sequence, determine the prevalence rate, and disclose risk factors for this sequence. We identified 270 cases defined as having some skin evidence of constriction band, plus those having limb defects suggestive of ADAM sequence, among 3,020,896 live and stillborns in the years 1982 to 1998 in ECLAMC (Latin American Collaborative Study of Congenital Malformations). Half of the cases presented mutilation (reduction), and deformity (ring constriction) affecting distal parts of fingers or toes bilaterally, without associated defects. Acrania, cephalocele, typical or atypical facial clefts, eyelid coloboma, and celosomia were also observed being significantly associated with the skin lesion. One affected infant in every 11,200 births, was found with stable trends during the last 17 years. There was an excess of cases in populations living at high altitude, stillborns, and neonatal infant dead. Among ADAM cases there was an excess of mothers with a prenatal history of febrile acute illness, medication drug use, or vaginal bleeding during the first trimester of pregnancy. Higher than expected frequencies of first‐born child, premature birth, low birth weight for gestational length, and non‐cephalic fetal presentation were also found. The observed geographic difference in birth prevalence could be a useful indication to study specific genetic and environmental candidate factors to ADAM susceptibility.

Frequency of holoprosencephaly in the International Clearinghouse Birth Defects Surveillance Systems: Searching for population variations

BACKGROUND Holoprosencephaly (HPE) is a developmental field defect of the brain that results in incomplete separation of the cerebral hemispheres that includes less severe phenotypes, such as arhinencephaly and single median maxillary central incisor. Information on the epidemiology of HPE is limited, both because few population-based studies have been reported, and because small studies must observe a greater number of years in order to accumulate sufficient numbers of births for a reliable estimate. METHODS We collected data from 2000 through 2004 from 24 of the 46 Birth Defects Registry Members of the International Clearinghouse for Birth Defects Surveillance and Research. This study is based on more than 7 million births in various areas from North and South America, Europe, and Australia. RESULTS A total of 963 HPE cases were registered, yielding an overall prevalence of 1.31 per 10,000 births. Because the estimate was heterogeneous, possible causes of variations among populations were analyzed: random variation, under-reporting and over-reporting bias, variation in proportion of termination of pregnancies among all registered cases and real differences among populations. CONCLUSIONS The data do not suggest large differences in total prevalence of HPE among the studied populations that would be useful to generate etiological hypotheses.