Detection of Streptococcus mutans Genomic DNA in Human DNA Samples Extracted from Saliva and Blood

Caries is a multifactorial disease, and studies aiming to unravel the factors modulating its etiology must consider all known predisposing factors. One major factor is bacterial colonization, and Streptococcus mutans is the main microorganism associated with the initiation of the disease. In our studies, we have access to DNA samples extracted from human saliva and blood. In this report, we tested a real-time PCR assay developed to detect copies of genomic DNA from Streptococcus mutans in 1,424 DNA samples from humans. Our results suggest that we can determine the presence of genomic DNA copies of Streptococcus mutans in both DNA samples from caries-free and caries-affected individuals. However, we were not able to detect the presence of genomic DNA copies of Streptococcus mutans in any DNA samples extracted from peripheral blood, which suggests the assay may not be sensitive enough for this goal. Values of the threshold cycle of the real-time PCR reaction correlate with higher levels of caries experience in children, but this correlation could not be detected for adults.

Racial gaps in child health insurance coverage in four South American countries: the role of wealth, human capital, and other household characteristics

OBJECTIVE. To evaluate the extent of racial gaps in child health insurance coverage in South America and study the contribution of wealth, human capital, and other household characteristics to accounting for racial disparities in insurance coverage. DATA SOURCES/STUDY SETTING. Primary data collected between 2005 and 2006 in 30 pediatric practices in Argentina, Brazil, Ecuador, and Chile. DESIGN. Country-specific regression models are used to assess differences in insurance coverage by race. A decomposition model is used to quantify the extent to which wealth, human capital, and other household characteristics account for racial disparities in insurance coverage. DATA COLLECTION/EXTRACTION METHODS. In-person interviews were conducted with the mothers of 2,365 children. PRINCIPAL FINDINGS. The majority of children have no insurance coverage except in Chile. Large racial disparities in insurance coverage are observed. Household wealth is the single most important household-level factor accounting for racial disparities in coverage and is significantly and positively associated with coverage, followed by maternal education and employment/occupational status. Geographic differences account for the largest part of racial disparities in insurance coverage in Argentina and Ecuador. CONCLUSIONS. Increasing the coverage of children in less affluent families is important for reducing racial gaps in health insurance coverage in the study countries.

The Impact of Maternal Smoking during Pregnancy on Early Child Neurodevelopment

Early child neurodevelopment has major impacts on future human capital and health. However, not much is known about the impacts of prenatal risk factors on child neurodevelopment. This study evaluates the effects of maternal smoking during pregnancy on child neurodevelopment between 3 and 24 months of age and interactions with socioeconomic status (SES). Data from a unique sample of children from South America are employed. Smoking has large adverse effects on neurodevelopment, with larger effects in the low SES sample. The study results highlight the importance of early interventions beginning before and during pregnancy for enhancing child development and future human capital attainment.

How valid are the rates of Down syndrome internationally? Findings from the International Clearinghouse for Birth Defects Surveillance and Research

Rates of Down syndrome (DS) show considerable international variation, but a systematic assessment of this variation is lacking. The goal of this study was to develop and test a method to assess the validity of DS rates in surveillance programs, as an indicator of quality of ascertainment. The proposed method compares the observed number of cases with DS (livebirths plus elective pregnancy terminations, adjusted for spontaneous fetal losses that would have occurred if the pregnancy had been allowed to continue) in each single year of maternal age, with the expected number of cases based on the best-published data on rates by year of maternal age. To test this method we used data from birth years 2000 to 2005 from 32 surveillance programs of the International Clearinghouse for Birth Defects Surveillance and Research. We computed the adjusted observed versus expected ratio (aOE) of DS birth prevalence among women 25-44 years old. The aOE ratio was close to unity in 13 programs (the 95% confidence interval included 1), above 1 in 2 programs and below 1 in 18 programs (P < 0.05). These findings suggest that DS rates internationally can be evaluated simply and systematically, and underscores how adjusting for spontaneous fetal loss is crucial and feasible. The aOE ratio can help better interpret and compare the reported rates, measure the degree of under- or over-registration, and promote quality improvement in surveillance programs that will ultimately provide better data for research, service planning, and public health programs.

Follow-up association studies of chromosome region 9q and nonsyndromic cleft lip/palate

Cleft lip/palate comprises a large fraction of all human birth defects, and is notable for its significant lifelong morbidity and complex etiology. Several studies have shown that genetic factors appear to play a significant role in the etiology of cleft lip/palate. Human chromosomal region 9q21 has been suggested in previous reports to contain putative cleft loci. Moreover, a specific region (9q22.3-34.1) was suggested to present a approximately 45% probability of harboring a cleft susceptibility gene. Fine mapping of 50 SNPs across the 9q22.3-34.11 region was performed to test for association with cleft lip/palate in families from United States, Spain, Turkey, Guatemala, and China. We performed family-based analyses and found evidence of association of cleft lip/palate with STOM (rs306796) in Guatemalan families (P = 0.004) and in all multiplex families pooled together (P = 0.002). This same SNP also showed borderline association in the US families (P = 0.04). Under a nominal value of 0.05, other SNPs also showed association with cleft lip/palate and cleft subgroups. SNPs in STOM and PTCH genes and nearby FOXE1 were further associated with cleft phenotypes in Guatemalan and Chinese families. Gene prioritization analysis revealed PTCH and STOM ranking among the top fourteen candidates for cleft lip/palate among 339 genes present in the region. Our results support the hypothesis that the 9q22.32-34.1 region harbors cleft susceptibility genes. Additional studies with other populations should focus on these loci to further investigate the participation of these genes in human clefting.

The impact of altitude on infant health in South America

Several studies report that altitude reduces birth weight. However, much remains unknown about effects in various altitude ranges and about the heterogeneity in altitude effects by fetal health endowments. This study estimates the effects of altitude in South America on the means and quantiles of birth weight and gestational age separately for two large samples born at altitude ranges of 5 to 1,280 m and 1,854 to 3,600 m. The study finds significant negative altitude effects on birth weight and gestational age in the low-altitude sample and on birth weight in the high-altitude sample. Altitude effects are larger for infants with very low fetal health endowments. The study finds differences in the effects of several inputs such as socioeconomic status and maternal fertility history and health between the two altitude samples. The study highlights the importance of adverse altitude effects on infant health when evaluating the costs and returns of policies that change the number of individuals who reside at higher altitude in both low and high altitude ranges.

CRISPLD2 variants including a C471T silent mutation may contribute to nonsyndromic cleft lip with or without cleft palate

OBJECTIVE

To assess the association between nonsyndromic (NS) cleft lip with or without cleft palate (CL(P)) and single-nucleotide polymorphisms (SNPs) within the CRISPLD2 gene (cysteine-rich secretory protein LCCL domain containing 2).

DESIGN

Four SNPs within the CRISPLD2 gene domain (rs1546124, rs8061351, rs2326398, rs4783099) were genotyped to test for association via family-based association methods.

PARTICIPANTS

A total of 5826 individuals from 1331 families in which one or more family member is affected with CL(P).

RESULTS

Evidence of association was seen for SNP rs1546124 in U.S. (p  =  .02) and Brazilian (p  =  .04) Caucasian cohorts. We also found association of SNP rs1546124 with cleft palate alone (CP) in South Americans (Guatemala and ECLAMC) and combined Hispanics (Guatemala, ECLAMC, and Texas Hispanics; p  =  .03 for both comparisons) and with both cleft lip with cleft palate (CLP; p  =  .04) and CL(P) (p  =  .02) in North Americans. Strong evidence of association was found for SNP rs2326398 with CP in Asian populations (p  =  .003) and with CL(P) in Hispanics (p  =  .03) and also with bilateral CL(P) in Brazilians (p  =  .004). In Brazilians, SNP rs8061351 showed association with cleft subgroups incomplete CL(P) (p  =  .004) and unilateral incomplete CL(P) (p  =  .003). Prediction of SNP functionality revealed that the C allele in the C471T silent mutation (overrepresented in cases with CL(P) presents two putative exonic splicing enhancer motifs and creates a binding site AP-2 alpha, a transcription factor involved in craniofacial development.

CONCLUSIONS

Our results support the hypothesis that variants in the CRISPLD2 gene may be involved in the etiology of NS CL(P).

Novel cleft susceptibility genes in chromosome 6q

Cleft lip/palate is a defect of craniofacial development. In previous reports, chromosome 6q has been suggested as a candidate region for cleft lip/palate. A multipoint posterior probability of linkage analysis of multiplex families from the Philippines attributed an 88% probability of harboring a cleft-susceptibility gene to a narrower region on bands 6q14.2-14.3. We genotyped 2732 individuals from families and unrelated individuals with and without clefts to investigate the existence of possible cleft-susceptibility genes in this region. We found association of PRSS35 and SNAP91 genes with cleft lip/palate in the case-control cohort and in Caucasian families. Haplotype analyses support the individual associations with PRSS35. We found Prss35 expression in the head and palate of mouse embryos at critical stages for palatogenesis, whereas Snap91 was expressed in the adult brain. We provide further evidence of the involvement of chromosome 6q in cleft lip/palate and suggest PRSS35 as a novel candidate gene.

Exposure of pregnant women to indoor air pollution: a study from nine low and middle income countries

OBJECTIVE

We studied exposure to solid fuel and second-hand tobacco smoke among pregnant women in south Asia, Africa and Latin America.

DESIGN

Prospective cross-sectional survey.

SETTING

Antenatal clinics in Argentina, Brazil, Ecuador, Guatemala, Uruguay, Democratic Republic of Congo, Zambia, India and Pakistan.

SAMPLE

A total of 7,961 pregnant women in ten sites in nine countries were interviewed between October 2004 and September 2005.

METHODS

A standardized questionnaire on exposure to indoor air pollution (IAP) and second-hand smoke was administered to pregnant women during antenatal care.

MAIN OUTCOME MEASURES

Exposure to IAP and second-hand tobacco smoke.

RESULTS

South Asian pregnant women commonly reported use of wood (49.1-89.7%), crop residue and animal dung as cooking and heating fuel. African pregnant women reported higher use of charcoal (85.4-93.5%). Latin American pregnant women had greater use of petroleum gas. Among south Asian women, solid fuel use and cooking on an open flame inside the home were common. There was a significant association between solid fuel use and allowing smoking within the home at the Asian sites and in Zambia (p < 0.05).

CONCLUSIONS

Pregnant women from low/middle income countries were commonly exposed to IAP secondary to use of solid fuels. Among these populations, exposure to second-hand tobacco smoke was also common. This combination of exposures likely increases the risk of poor pregnancy outcomes among the most vulnerable women. Our study highlights the importance of further research on the combined impact of IAP and second-hand tobacco smoke exposures on adverse maternal and perinatal outcomes.

[Smoking and exposure to tobacco smoke among pregnant women in Ecuador]

OBJECTIVES

To determine the frequency of smoking and second-hand smoke exposure among pregnant women in Ecuador and to describe the sociodemographic profiles associated with these perinatal risk factors.

METHODS

A cross-sectional descriptive study using a survey of women 18-46 years of age who were more than three months pregnant and attended follow-up consultations in seven maternity clinics in six cities in Ecuador between October 2004 and September 2005. Demographics and environmental exposure (independent variables) data and their relationship to cigarette smoking and secondhand-smoke exposure were analyzed.

RESULTS

Of the 746 women studied, 53.3% had smoked occasionally, and 4.3%, regularly; of these, 75% had quit smoking before or during pregnancy. Of the respondents, 12.9% were frequently or always exposed to secondhand smoke indoors. Having more education (11 or more years), being in the middle or upper socioeconomic classes, being Caucasian, and it being considered acceptable for women in the community to smoke were significantly and directly associated with cigarette smoking (P<0.001). Overall, 12.9% of women were being exposed to secondhand smoke and this was significantly associated with being single and cohabiting with smokers or employees connected to the tobacco industry (P<0.001).

CONCLUSIONS

Specific measures must be designed and implemented to not only encourage smoking cessation during pregnancy, but also to prevent women of reproductive age from taking up smoking and to limit smoking in the home environment.

Prenatal sonographic detection of birth defects in 18 hospitals from South America

OBJECTIVE

The purpose of this study was to assess the accuracy of prenatal sonographic diagnosis of birth defects and the gestational age at detection according to the health insurance schemes of mothers in 450 malformed neonates from 18 South American hospitals on the basis of prenatal sonographic records.

METHODS

Between July 2000 and December 2003, 18 hospitals included in the Latin American Collaborative Study of Congenital Malformations (13 from Argentina [8 public and 5 nonpublic], 3 from Brazil [2 public and 1 nonpublic], 1 from Chile [nonpublic], and 1 from Venezuela [public]) voluntarily participated in this prospective observational study, recording fetuses with sonographically detected malformations. Prenatal sonographic descriptions of anomalies were compared with those recorded at birth.

RESULTS

Of 812 anomalies detected at birth, 457 had been prenatally detected (detection rate, 56.3%; 95% confidence interval, 52.8%-59.8%). Before 24 gestational weeks, anencephaly had the highest detection rate. Cleft lip and clubfoot were more easily detected when associated with other anomalies. The detection rates for central nervous system and renourinary malformations were greater than 80%. Detection rates between both health insurance schemes (public and nonpublic) did not show significant differences, but anencephaly, spina bifida, renourinary defects, and cleft lip with or without cleft palate were detected earlier in patients from nonpublic rather than in public hospitals.

CONCLUSIONS

For specific anomalies, South America shows similar levels of prenatal sonographic detection as developed countries. Detection rates during pregnancy were similar for public and nonpublic hospitals, whereas cases were diagnosed earlier in patients from nonpublic hospitals.

Whorl patterns on the lower lip are associated with nonsyndromic cleft lip with or without cleft palate

Nonsyndromic cleft lip with or without cleft palate (CL/P) is a common birth defect due to both genetic and environmental factors. Whorl lip print patterns are circular grooves on the central upper lip and/or the left and right lower lip. To determine if whorls are more common in families with CL/P than in controls, the Pittsburgh Orofacial Cleft Study collected lip prints from over 450 subjects, that is, individuals with CL/P, their relatives, and unrelated controls-from the U.S., Argentina, and Hungary. Using a narrow definition of lower-lip whorl, the frequency of whorls in the U.S. sample was significantly elevated in cleft individuals and their family members, compared to unrelated controls (14.8% and 13.2% vs. 2.3%; P = 0.003 and 0.001, respectively). Whorls were more frequent in CL/P families from Argentina than in CL/P families from the U.S. or Hungary. If these results are confirmed, whorl lip print patterns could be part of an expanded phenotypic spectrum of nonsyndromic CL/P. As such, they may eventually be useful in a clinical setting, allowing recurrence risk calculations to incorporate individual phenotypic information in addition to family history data.

Isonymy structure of Buenos Aires city

The isonymy structure of Buenos Aires was studied based on its surname frequency. Information on 2,552,359 voters of the 28 Buenos Aires districts was used to estimate Lasker's coefficient of relationship by isonymy (R(i)), surname diversity according to Fisher's alpha, the coefficient of consanguinity resulting from random isonymy (F), and Nei's, Lasker's and the Euclidean isonymy distances. These distances were correlated with geographic distances, which were calculated by assigning an arbitrary point to each district and measuring distances on a map of the city. The R(i) x 10(5) and F x 10(4) averages of the districts located south of Rivadavia Avenue were higher (R(i) = 66.08; F = 3.4) than those situated north of that avenue (R(i) = 46.60; F = 2.4) (p < 0.001). Fisher's alpha showed the opposite behavior (north, alpha = 1,055.5; south, alpha = 757.2). There was a significant correlation (p < 0.001) between geographic distance and Nei's and the Euclidean distances (0.496 and 0.503, respectively), but the correlation was not significant for Lasker's distance (0.051). These results indicate isolation by distance in the city of Buenos Aires and reveal subdivision of the metropolitan population, with greater consanguinity and a lesser variety of surnames in the districts located in the southern section of the city. This structure agrees with the fragmentation and social, cultural, and economic differences observed among the districts of this Latin American metropolis.

Quantile effects of prenatal care utilization on birth weight in Argentina

The effects of prenatal care utilization on birth weight (BW) may vary by unobserved fetal health endowments. This heterogeneity will be masked by estimating the effects at BW mean but can be evaluated by estimating the effects at BW quantiles as fetal health endowment is a strong correlate with the BW quantile order. We estimated the effects of prenatal care visits and delay before prenatal care initiation, on BW mean and quantiles using a sample of infants from Argentina. Self-selection into prenatal care was modeled using 2SLS and instrumental variable quantile regression. Results suggest that the 'mean' effect of prenatal care utilization largely underestimates the effects at lower BW quantiles. About 35 and 77 g increase in BW mean and 0.1 quantile respectively, per visit and about 30 and 139 g decrease in BW mean and 0.1 quantile respectively, per week delayed, were estimated. Ignoring self-selection into prenatal care resulted in underestimation of mean and quantile effects. Results highlight the limitation of analyses focused on 'mean effects' in the presence of treatment heterogeneity and emphasize the importance of identifying women at risk for having infants at lower BW quantiles as they may benefit most from earlier and more intensive prenatal care.

Predictors of multivitamin use during pregnancy in Brazil

OBJECTIVES

The study aimed at identifying predictors of multivitamin use during pregnancy in Brazil.

METHODS

Birth registry data of 1,774 infants at maternity hospitals in Brazil were used. The effects of maternal health and fertility risk indicators, enabling factors and other maternal characteristics on multivitamin use were evaluated both pooled and stratified by African ancestry.

RESULTS

About 14% of the women used multivitamins during pregnancy. Number of previous live births, maternal age and education, number of ultrasound exams and year of pregnancy had significant effects on multivitamin use in the group reporting African ancestry. Maternal acute illnesses and education had significant effects on use in the group without African ancestry. Significant geographic variation in multivitamin use was observed in both groups.

CONCLUSIONS

The study identifies several risk indicators, health care access and enabling factors that are predictive of multivitamin use with differences by African ancestry. The study highlights the importance of increasing the awareness of women of childbearing age of the benefits of multivitamin use and identifies barriers that need to be addressed to promote use.

Prenatal care effectiveness and utilization in Brazil

The impact of prenatal care use on birth outcomes has been understudied in South American countries. This study assessed the effects of various measures of prenatal care use on birth weight (BW) and gestational age outcomes using samples of infants born without and with common birth defects from Brazil, and evaluated the demand for prenatal care. Prenatal visits improved BW in the group without birth defects through increasing both fetal growth rate and gestational age, but prenatal care visits had an insignificant effect on BW in the group with birth defects when adjusting for gestational age. Prenatal care delay had no effects on BW in both infant groups but increased preterm birth risk in the group without birth defects. Inadequate care versus intermediate care also increased LBW risk in the group without birth effects. Quantile regression analyses revealed that prenatal care visits had larger effects at low compared with high BW quantiles. Several other prenatal factors and covariates such as multivitamin use and number of previous live births had significant effects on the studied outcomes. The number of prenatal care visits was significantly affected by several maternal health and fertility indicators. Significant geographic differences in utilization were observed as well. The study suggests that more frequent use of prenatal care can increase BW significantly in Brazil, especially among pregnancies that are uncomplicated with birth defects but that are at high risk for low birth weight. Further research is needed to understand the effects of prenatal care use for pregnancies that are complicated with birth defects.

Clusters of sirenomelia in South America

BACKGROUND

One hospital in the city of Cali, Colombia, of the ECLAMC (Latin-American Collaborative Study of Congenital Malformations) network, reported the unusual occurrence of four cases of sirenomelia within a 55-day period.

METHODS

An ECLAMC routine for cluster evaluation (RUMOR) was followed that included: calculations of observed/expected ratios, site visits, comparison with comprehensively collected local, South American, and worldwide data, cluster analysis, and search for risk factors.

RESULTS

All four Cali sirenomelia cases were born to mothers living in a 2 km(2) area, in neighboring communes, within the municipality of Cali. Considering the total births of the city of Cali as the denominator, and based on ECLAMC baseline birth prevalence rates (per 100,000) for sirenomelia (2.25, 95% CI: 2.66, 3.80), the cluster for this congenital abnormality was unlikely to have occurred by chance (observed/expected ratio = 5.77; 95% CI: 1.57-14.78; p = .002). No consistent common factor was identified, but vicinity to an open landfill as the cause could not be rejected. Another ECLAMC hospital in San Justo, Buenos Aires, Argentina, reported three further cases but these did not seem to constitute a nonrandom cluster.

CONCLUSIONS

The methodology used to evaluate the two possible clusters of sirenomelia determined that the Cali sirenomelia cluster was unlikely to have occurred by chance whereas the sirenomelia cluster from San Justo seemed to be random.

Prenatal care demand and its effects on birth outcomes by birth defect status in Argentina

Our objective was to identify determinants of prenatal care demand and evaluate the effects of this demand on low birth weight and preterm birth. Delay in initiating prenatal care was modeled as a function of pregnancy risk indicators, enabling factors, and regional characteristics. Conditional maximum likelihood (CML) estimation was used to model self-selection into prenatal care use when estimating its effectiveness. Birth registry data was collected post delivery on infants with and without common birth defects born in 1995-2002 in Argentina using a standard procedure. Several maternal health and fertility indicators had significant effects on prenatal care use. In the group without birth defects, prenatal care delay increased significantly LBW and preterm birth when accounting for self-selection using the CML model but not in the standard probit model. Prenatal care was found to be ineffective on average in the birth defect group. The self-selection of higher risk women into earlier initiation of prenatal care resulted in underestimation of prenatal care effectiveness when using a standard probit model with several covariates. Large improvements in birth outcomes are suggested with earlier initiation of prenatal care for pregnancies uncomplicated with birth defects in Argentina, implying large opportunity costs from the long waiting time observed in this sample (about 17 weeks on average). The suggested ineffectiveness for pregnancies complicated with common birth defects deserves further research.

Preferential associations between oral clefts and other major congenital anomalies

OBJECTIVES

To identify preferential associations between oral clefts (CL = cleft lip only, CLP = cleft lip with cleft palate, CP = cleft palate) and nonoral cleft anomalies, to interpret them on clinical grounds, and, based on the patterns of associated defects, to establish whether CL and CLP are different conditions.

DESIGN AND SETTINGS

Included were 1416 cleft cases (CL = 131, CLP = 565, CP = 720), among 8304 live- and stillborn infants with multiple congenital anomalies, from 6,559,028 births reported to the International Clearinghouse for Birth Defects Surveillance and Research by 15 registries between 1994 and 2004. Rates of associated anomalies were established, and multinomial logistic regressions applied to identify significant associations.

RESULTS

Positive associations with clefts were observed for only a few defects, among which anencephaly, encephaloceles, club feet, and ear anomalies were the most outstanding. Anomalies negatively associated with clefts included congenital heart defects, VATER complex (vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia), and spina bifida.

CONCLUSION

The strong association between all types of clefts and anencephaly seems to be attributable to cases with disruptions; the association between CP and club feet seems to be attributable to conditions with fetal akinesia. Some negative associations may depend on methodologic factors, while others, such as clefts with VATER components or clefts with spina bifida, may depend on biological factors. The different patterns of defects associated with CL and CLP, indicating different underlying mechanisms, suggest that CL and CLP reflect more than just variable degrees of severity, and that distinct pathways might be involved.

Sirenomelia and cyclopia cluster in Cali, Colombia

Sirenomelia and cyclopia share etiologic and pathogenic characteristics. A cluster of these two patterns of malformation in the city of Cali, Colombia, is described. Four sirenomelia and four cyclopia cases were born within a 165 days period in one hospital in Cali. The lapse between conception dates of first and last cases was shorter for sirenomelia (53 days) than for cyclopia (231 days). Based on ECLAMC (Latin American Collaborative Study of Congenital Malformations) published data, the observed/expected ratio (5.7) for both defects is statistically significant (P < 0.001). Mother's residence during the first trimester of pregnancy is concentrated in a same city quarter for four of the eight cases, close to a know polluting active landfill, and the other four cases, along the Cauca river, downstream from this landfill. Birth prevalence rates for two sentinel anomalies, that is, anal and esophageal atresia for sirenomelia and oral clefts for DeMyer holoprosencephaly spectra, were not higher in Cali than in the rest of ECLAMC material. The Computer Assisted Telephone Interviewing was applied to mothers of the 8 patients, and 32 matched controls. Seven of 295 variables were associated with sirenomelia, 3 of them related to house tap water, one to exposure to street drugs, one to physical injury, and 2 secondary to abnormal pregnancy outcome. None was associated with cyclopia. Results from hair dosage of heavy metals in the 8 patient's mothers were inconsistent. The time-space cluster is nonrandom for sirenomelia, and possibly random for cyclopia. The polluting landfill remains as a possible etiological factor.

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.

Brazil: public health genomics

Brazil represents half of South America and one third of Latin America, having more than 186 million inhabitants. After China and India it is the third largest developing country in the world. The wealth is unequally distributed among the states and among the people. Brazil has a large and complex health care system. A Universal Public Health System (SUS: Sistema SPACEnico de Saúde) covers the medical expenses for 80% of the population. The genetic structure of the population is very complex, including a large proportion of tri- hybrid persons, genetic isolates, and a panmictic large majority. Genetic services are offered at 64 genetic centers, half of them public and free. Nationwide networks are operating for inborn errors of metabolism, oncogenetics, and craniofacial anomalies. The Brazilian Society of Medical Genetics (SBGM) has granted 120 board certifications since 1986, and 7 recognized residences in medical genetics are operating in the country. Three main public health actions promoted by the federal government have been undertaken in the last decade, ultimately aimed at the prevention of birth defects. Since 1999, birth defects are reported for all 3 million annual live births, several vaccination strategies aim at the eradication of rubella, and wheat and maize flours are fortified with folic acid. Currently, the government distributes over 2 million US dollars to finance 14 research projects aimed at providing the basis for the adequate prevention and care of genetics disorders through the SUS. Continuity of this proactive attitude of the government in the area of genomics in public health is desired.