The Chilean socio-ethno-genomic cline

Studies of the current Chilean population performed using classical genetic markers have established that the Chilean population originated primarily from the admixture of European people, particularly Spaniards, and Amerindians. A socioeconomic-ethno-genetic cline was established soon after the conquest. Spaniards born in Spain or Chile occupied the highest Socioeconomic Strata, while Amerindians belonged to the lowest. The intermediate strata consisted of people with different degrees of ethnic admixture; the larger the European admixture, the higher the Socioeconomic Level. The present study of molecular genomic markers sought to calculate the percentage of Amerindian admixture and revealed a finer distribution of this cline, as well as differences between two Amerindian groups: Aymara and Mapuche. The use of two socioeconomic classifications - Class and Socioeconomic Level - reveals important differences. Furthermore, Self-reported Ethnicity (self-assignment to an ethnic group) and Self-reported Ancestry (self-recognition of Amerindian ancestors) show variations and differing relationships between socioeconomic classifications and genomic Amerindian Admixture. These data constitute a valuable input for the formulation of public healthcare policy and show that the notions of Ethnicity, Socioeconomic Strata and Class should always be a consideration in policy development.

[Growth hormone of dried blood spot for the diagnosis of growth hormone deficiency]

INTRODUCTION

The diagnosis of growth hormone deficiency (GHD) is difficult to determine, and could be associated with severe complications, especially in the neonatal period. The stimulation test of growth hormone (GH) secretion is considered the gold standard for diagnosis, but it has methodological complications and is associated with adverse effects. Neonates present physiological increased secretion of GH, representing a diagnostic window.

OBJECTIVE

To evaluate if the dried blood spot on filter paper obtained in the neonatal period, as part of a neonatal screening for con genital hypothyroidism and phenylketonuria, allows differentiating patients with GHD from those who do not have it.

PATIENTS AND METHOD

Study of cases and controls by measuring the GH concen tration in dried blood spot on filter paper obtained in the neonatal period, comparing controls with GHD with cases with discarded deficiency. The sample was extracted from the filter paper, obtaining two 0.125 inch discs per each patient from the center of the blood spot on the paper, for a highly sen sitive ELISA assay for human GH based on the use of polyclonal antibodies against 22 kDa recom binant human GH.

RESULTS

Seven cases of GHD and ten controls were obtained. The median GH concentration of the dried blood spot in the cases is 2.0 ng/ml (Interquartile range 3.6 ng/ml) and 2.05 ng/ml (Interquartile range 2.0 ng/ml) in the controls, Mann-Whitney U test 30.5 (p = 0.68). The two cases with multiple pituitary-hormone deficiency (MPHD) present concentrations lower than 1 ng/ml.

CONCLUSION

The dried blood spot sample did not differentiate GHD patients from control cases, although MPHD cases present much lower concentrations compared to isolated growth hor mone deficiency (IGHD).

Pollen derived low molecular compounds enhance the human allergen specific immune response in vivo

BACKGROUND

Besides allergens, pollen release bioactive, low molecular weight compounds that modulate and stimulate allergic reactions. Clinical relevance of these substances has not been investigated to date.

OBJECTIVE

To elucidate the effect of a non-allergenic, low molecular weight factors from aqueous birch pollen extracts (Bet-APE < 3 kDa) on the human allergic immune response in vivo.

METHODS

Birch and grass pollen allergic individuals underwent skin prick testing with allergen alone, allergen plus Bet-APE < 3 kDa, or allergen plus pre-identified candidate substances from low molecular pollen fraction. Nasal allergen challenges were performed in non-atopic and pollen allergic individuals using a 3 day repeated threshold challenge battery. Subjects were either exposed to allergen alone or to allergen plus Bet-APE< 3 kDa. Local cytokine levels, nasal secretion weights, nasal congestion and symptom scores were determined.

RESULTS

Skin prick test reactions to pollen elicited larger weals when allergens were tested together with the low molecular weight compounds from pollen. Similar results were obtained with candidate pollen-associated lipid mediators. In nasal lining fluids of allergic patients challenged with allergen plus Bet-APE < 3 kDa, IL-8 and IgE was significantly increased as compared to allergen-only challenged patients. These patients also produced increased amounts of total nasal secretion and reported more severe rhinorrhea than the allergen-only challenged group.

CONCLUSIONS

Low molecular compounds from pollen enhance the allergen specific immune response in the skin and nose. They are therefore of potential clinical relevance in allergic patients.

Rapid molecular detection of pulmonary tuberculosis in HIV-infected patients in Santiago, Chile

SETTING

Santiago, Chile, has a mean annual tuberculosis (TB) rate of 13 per 100 000 population; however, TB incidence in human immunodeficiency virus (HIV) infected individuals is at least 20 times higher.

OBJECTIVE

To assess the accuracy of rapid molecular testing for pulmonary TB (PTB) detection in routine care in HIV-infected patients.

DESIGN

Cross-sectional study, conducted prospectively in five hospitals between March 2010 and June 2011. HIV-positive subjects with suspected PTB provided sputum or mouth wash samples that were directly processed for acid-fast smear, mycobacterial cultures and Xpert® MTB/RIF. Positive test results were reported on the same day.

RESULTS

We enrolled 166 subjects into the study; 50.6% provided two sputum samples, 33.1% only one sputum sample and 16.3% a mouth wash sample. The prevalence of TB was 8.1% (13/160). Diagnostic sensitivity increased from 66.7% (95%CI 39.1-86.2) for acid-fast smear to 91.7% (95%CI 64.6-98.5) for Xpert MTB/RIF, with comparable specificity at 98.6% (146/148, 95%CI 95.2-99.6) and 99.3% (147/148, 95%CI 96.3-99.9). Xpert MTB/RIF allowed early detection of rifampicin resistance in 16.6% of cases, with rapid adjustment to multidrug-resistant treatment.

CONCLUSION

Xpert MTB/RIF provided earlier TB diagnosis in 25% more cases than acid-fast smear alone. Its implementation should be considered for TB diagnosis in HIV-positive patients even outside TB-endemic areas.

The putative serine protease inhibitor Api m 6 from Apis mellifera venom: recombinant and structural evaluation

BACKGROUND

Immunoglobulin (Ig) E-mediated reactions to honeybee venom can cause severe anaphylaxis, sometimes with fatal consequences. Detailed knowledge of the allergic potential of all venom components is necessary to ensure proper diagnosis and treatment of allergy and to gain a better understanding of the allergological mechanisms of insect venoms.

OBJECTIVE

Our objective was to undertake an immunochemical and structural evaluation of the putative low-molecular-weight serine protease inhibitor Api m 6, a component of honeybee venom.

METHODS

We recombinantly produced Api m 6 as a soluble protein in Escherichia coli and in Spodoptera frugiperda (Sf9) insect cells.We also assessed specific IgE reactivity of venom-sensitized patients with 2 prokaryotically produced Api m 6 variants using enzyme-linked immunosorbent assay. Moreover, we built a structural model ofApi m 6 and compared it with other protease inhibitor structures to gain insights into the function of Api m 6.

RESULTS

In a population of 31 honeybee venom-allergic patients, 26% showed specific IgE reactivity with prokaryotically produced Api m 6, showing it to be a minor but relevant allergen. Molecular modeling of Api m 6 revealed a typical fold of canonical protease inhibitors, supporting the putative function of this venom allergen. Although Api m 6 has a highly variant surface charge, its epitope distribution appears to be similar to that of related proteins.

CONCLUSION

Api m 6 is a honeybee venom component with IgE-sensitizing potential in a fraction of venom-allergic patients. Recombinant Api m 6 can help elucidate individual component-resolved reactivity profiles and increase our understanding of immune responses to low-molecular-weight allergens

Api m 10, a genuine A. mellifera venom allergen, is clinically relevant but underrepresented in therapeutic extracts

BACKGROUND

Generalized systemic reactions to stinging hymenoptera venom constitute a potentially fatal condition in venom-allergic individuals. Hence, the identification and characterization of all allergens is imperative for improvement of diagnosis and design of effective immunotherapeutic approaches. Our aim was the immunochemical characterization of the carbohydrate-rich protein Api m 10, an Apis mellifera venom component and putative allergen, with focus on the relevance of glycosylation. Furthermore, the presence of Api m 10 in honeybee venom (HBV) and licensed venom immunotherapy preparations was addressed.

METHODS

Api m 10 was produced as soluble, aglycosylated protein in Escherichia coli and as differentially glycosylated protein providing a varying degree of fucosylation in insect cells. IgE reactivity and basophil activation of allergic patients were analyzed. For detection of Api m 10 in different venom preparations, a monoclonal human IgE antibody was generated.

RESULTS

Both, the aglycosylated and the glycosylated variant of Api m 10 devoid of cross-reactive carbohydrate determinants (CCD), exhibited IgE reactivity with approximately 50% of HBV-sensitized patients. A corresponding reactivity could be documented for the activation of basophils. Although the detection of the native protein in crude HBV suggested content comparable to other relevant allergens, three therapeutical HBV extracts lacked detectable amounts of this component.

CONCLUSION

Api m 10 is a genuine allergen of A. mellifera venom with IgE sensitizing potential in a significant fraction of allergic patients independent of CCD reactivity. Thus, Api m 10 could become a key element for component-resolved diagnostic tests and improved immunotherapeutic approaches in hymenoptera venom allergy.

Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczema

BACKGROUND

Prior to the discovery of filaggrin (FLG) mutations, evidence for an impaired skin barrier in atopic dermatitis (AD) has been documented, and changes in ceramide profile, altered skin pH and increased trans-epidermal water loss (TEWL) in patients with AD have been reported. Until now, no studies have analysed stratum corneum (SC) lipids combined with skin barrier parameters in subjects of known FLG genotype.

METHODS

A cohort of 49 German individuals genotyped for the most common FLG mutations (R501X, 2282del4) had SC samples taken for lipid analysis by high-performance thin layer chromatography. In addition, TEWL, erythema, skin hydration and pH were measured. In 27 of the 49 individuals, a 24-h irritation patch test with sodium lauryl sulphate was performed. For the analysis, both the AD group and the control group were stratified by FLG mutation status (FLGmut/FLGwt).

RESULTS

In the FLGmut AD group, significantly lower levels of ceramide 4 and significantly higher levels of ceramide 7 were observed when compared to both healthy control groups. However, ceramide 7 levels also significantly differed between FLGwt AD and FLGwt controls, as did ceramide 1 levels. No significant differences were observed for ceramide 2, 3, 5 and 6. FLGmut individuals had significantly higher skin pH values than individuals not carrying FLG mutations. Patients with AD with FLG mutations had significantly higher erythema compared to patients with AD without FLG mutations.

CONCLUSION

Our results confirm previous observations of altered ceramide levels in AD, which however appear to show no clear relationship with FLG mutations.

CTG repeats at the myotonic protein kinase gene in a healthy Chilean population sample

OBJECTIVES

To study the variability at the myotonic dystrophy protein kinase (DMPK) gene in a Chilean sample of healthy people. DM1 is an autosomal dominant disorder caused by an expansion of a (CTG) repeat at the 3'-UTR of the gene DMPK. Healthy individuals have alleles under 35 repeats and diseased individuals have over 50.

METHODS

Genotyping the number of (CTG) repeats at this gene in a sample of healthy Chilean people.

RESULTS

Allele frequencies were significantly different from those of other populations. The most frequent allele was with five repeats. The frequency of larger alleles (>18 CTG repeats) was 11%, close to the European frequency (12%) and higher than the Japanese (8%) and Aboriginal Pehuenche samples (8%).

CONCLUSIONS

Allelic frequencies in the Chilean sample studied were intermediate between those of the two ancestral populations (European and Pehuenche).

Genetic variants in the enhancer region of the thymidylate synthase gene in the Chilean population

AIMS

Thymidylate synthase (TYMS) is an important target enzyme for the fluoropyrimidines. The TYMS gene enhancer region possesses tandemly repeated (TSER) sequences that are polymorphic in humans and different among ethnic groups. The aims of this study were to estimate the frequencies of the TSER variants in two hospital samples located in the northern (HSJ) and eastern (CLC) parts of Santiago, Chile, and compare them with the frequencies in other populations of different ethnic origin.

METHODS

Genotyping of TSER variants in 368 Chilean subjects (HSJ = 178 and CLC = 190) by polymerase chain reaction; products of amplification were electrophoresed, obtaining fragments of 250 bp for allele TSER*3 and 220 bp for allele TSER*2.

RESULTS

The two hospital samples had different degrees of Amerindian admixture (HSJ 34.5%; CLC 15.9%), which was not reflected in the observed frequencies of the CLC TSER*3: 56.8% and HSJ TSER*3: 53.4%.

CONCLUSIONS

Our results are unexpected, considering that genetic markers in the Chilean population generally show allele frequencies between those observed in European Caucasians and Amerindians and that the percentage of Amerindian admixture in CLC is lower than in HSJ. Both hospitals should have had greater frequencies of TSER*3 than were found and the frequency should have been greater in HSJ than in CLC; the only logical explanation of our results is that the frequency of this allele in aboriginal Chilean people is much lower than the 80% estimated for Mongoloid populations.

DYS19 and DYS199 loci in a Chilean population of mixed ancestry

The current Chilean population originated from admixture between aboriginal populations (Amerindians) and Spanish conquerors of European origin. Consequently, the unions that gave rise to the Chilean population were chiefly between Spanish males and aboriginal females, and not the converse. To test the hypothesis that the Y chromosome of the Chilean population is mainly of Spanish origin, while the other chromosomes are from mixed (European and aboriginal) origin, we studied the DYS19 and DYS199 loci in two samples. One sample was obtained from a high socioeconomic stratum, while a second sample was from a low stratum. We studied male blood donors (N = 187) from Santiago, the capital of the country. Subjects were typed for the autosomal ABO and Rh (locus D) blood groups, and for the Y-linked DYS19 and the DYS199 loci, reported as Y-chromosome haplotypes. The aboriginal admixture was estimated for each genetic marker. The percentage of aboriginal admixture was 38.17% for the ABO system and 31.28% for the Rh system in the low socioeconomic stratum and 19.22% and 22.5%, respectively, in the high stratum. Y-chromosome haplotype frequencies constructed from the DYS19 and DYS199 loci demonstrated that the main haplotypes were DYS19*14/DYS199 C, as is often the case with many European populations, and DYS19*13/DYS199 C. The aboriginal admixture from Y-haplotype frequencies was estimated to be 15.83% in the low socioeconomic stratum and 6.91% in the high stratum. These values are lower than the values found using autosomal genetic markers, and are consistent with the historical background of the population studied. This study highlights the population genetic consequences of the asymmetric pattern of genome admixture between two ancestral populations (European and Amerindian).

Genetic Variants of the Paraoxonases ( PON1 and PON2 ) in the Chilean Population

We estimated the frequencies of PON1 and PON2 variants (linked genes) in two hospital samples taken from the northern (San José Hospital, SJH) and eastern (Clínica Las Condes, CLC) parts of Santiago, Chile, using the polymerase chain reaction followed by restriction endonuclease digestion. The two hospital samples have different degrees of Amerindian admixture (SJH, 34.5%; CLC, 15.9%), which is reflected in the observed frequencies of the PON1 *B allele (SJH, 43.1%; CLC, 33.7%) and the PON2*S allele (SJH, 86.3%; CLC, 77.6%); both allele frequencies are significantly different between samples. The frequencies of the combined PON1-PON2 genotypes *A/*B-*C/*C, *A/*B-*S/*S, and *B/*B-*S/*S and of the haplotypes PON*A,C and PON*B,S were significantly different between the SJH and CLC groups. None of the genotype frequencies deviated significantly from those predicted by the Hardy-Weinberg equation. No linkage disequilibrium was found between the PON1 alleles and any of the PON2 alleles in either group (all p > 0.05). In our samples 38.52% (SJH) and 26.25% (CLC) of chromosomes must have the haplotype PON*B,S, presumed to be related to the risk of coronary artery disease. Twenty-four of 193 (12.4%) SJH individuals and 7 of 122 (5.7%) CLC individuals were homozygotes for this haplotype. Finally, our data indicate ethnic-group-dependent genetic differences in the vulnerability to toxic organophosphorus.

Genetic variants of serum butyrylcholinesterase in Chilean Mapuche Indians

We estimated the frequencies of serum butyrylcholinesterase (BChE) alleles in three tribes of Mapuche Indians from southern Chile, using enzymatic methods, and we estimated the frequency of allele BCHE*K in one tribe using primer reduced restriction analysis (PCR-PIRA). The three tribes have different degrees of European admixture, which is reflected in the observed frequencies of the atypical allele BCHE*A: 1.11% in Huilliches, 0.89% in Cuncos, and 0% in Pehuenches. This result is evidence in favor of the hypothesis that BCHE*A is absent in native Amerindians. The frequencies of BCHE*F were higher than in most reported studies (3.89%, 5.78%, and 4.41%, respectively). These results are probably due to an overestimation of the frequency of allele BCHE*F, since none of the 20 BCHE UF individuals (by the enzymatic test) individuals analyzed showed either of the two DNA base substitutions associated with this allele. Although enzymatic methods rarely detect the presence of allele BCHE*K, PCR-PIRA found the allele in an appreciable frequency (5.76%), although lower than that found in other ethnic groups. Since observed frequencies of unusual alleles correspond to estimated percentages of European admixture, it is likely that none of these unusual alleles were present in Mapuche Indians before the arrival of Europeans.

Frequency of the hypervariable DNA loci D18S849, D3S1744, D12S1090 and D1S80 in a mixed ancestry population of Chilean blood donors

Blood donors (N = 150) at San José Hospital (Santiago, Chile) were typed for one VNTR locus (D1S80) and three STR loci (D18S849, D3S1744, D12S1090). A questionnaire was used to determine the socioeconomic level of the donors, because it is known that some genetic markers (e.g., the ABO and Rh groups) are differentially distributed between different socioeconomic strata. This methodology revealed that two of the three socioeconomic strata distinguishable in Santiago were present in our sample of blood donors, with stratum II representing the middle strata and stratum III the low strata. Allele frequency was determined for each locus and socioeconomic stratum, and it was found that the allele distributions of each locus in socioeconomic strata II and III were statistically similar. All loci conformed to the Hardy-Weinberg law and there was no evidence for association between the alleles of the four loci, allelic frequencies being similar to those found in North American Hispanic populations. The results support the view that the analysis of these loci may have useful applications in population genetics as well as in identity tests.

[Central nervous system malformations in a Clinical Hospital of Universidad de Chile and in Chilean maternity hospitals that participated in the Latin American Collaborative Study of Congenital Malformations (ECLAMC)]

BACKGROUND

In Chile, the rates of central nervous system congenital malformations at birth remain high, when compared with the rest of the world.

AIM

To report the rates of central nervous system congenital malformations in Chilean hospitals.

MATERIAL AND METHODS

Using the ECLAMC protocol, every malformed newborn or stillbirth, weighing more than 500 g at birth is registered using a standard protocol, and the next non malformed child of the same sex born in the same hospital is assigned as control.

RESULTS

The rates of central nervous system congenital malformations are higher at the University of Chile Clinical Hospital than in the rest of Chilean hospitals or Latin American Hospitals. There are significantly higher rates of anencephalia in Concepcion and spina bifida in Valdivia, Rancagua and Concepcion. In the University of Chile Clinical Hospital, global annual rates have a negative slope of -0.0259 per 1000 born alive, with a correlation coefficient of -0.125 (p < 0.05). The slope is positive among children born alive, with an annual rate increase of 0.071. Among stillbirths, the slope is -0.47 per 1000 born alive. Sixty two percent of malformed children were female. Among children with neural tube defects, 30% had a malformed relative and, of these, 66% had the same malformation.

CONCLUSIONS

Family clustering of neural tube defects, supports the influence of a genetic factor influencing their appearance.

[Congenital malformations in Chile. An emerging problem (period 1995-1999)]

BACKGROUND

The Latin American collaborative study of congenital malformations (ECLAMC) is a surveillance program designed to monitor the frequency of congenital malformations and detect abrupt changes in their frequency, look for the cause of such change and implement primary prevention measures.

AIM

To construct a secular trend curve with the frequency of congenital malformations in Chile.

MATERIAL AND METHODS

Using the ECLAMC protocol, every malformed newborn or stillbirth, weighting more than 500 g at birth is registered using a standard protocol, and the next non malformed child of the same sex born in the same hospital is assigned as control. Using the gathered data, secular trend curves of congenital malformations were constructed.

RESULTS

Between 1982 and 1999, there is a secular tendency in the rate of congenital malformations and maternal age, with a correlation coefficient of 0.8 and slope of 13.5 (p < 0.05). The rates of congenital malformations at the moment of birth are higher at the University of Chile Clinical Hospital than in the rest of Chilean hospitals and other Latin American Hospitals. Anencephaly is a defect with a high frequency in Concepción and spina bifida has a high frequency in Rancagua, Viña del Mar, Concepción and Valdivia. There is an impressive increase in malformations dependent on prenatal diagnosis such as kidney agenesis, polycystic kidney and diaphragmatic hernia.

CONCLUSIONS

Congenital malformations are having an increasing importance as causes of morbidity or mortality in the newborn.

Assessing the health benefits of urban air pollution reductions associated with climate change mitigation (2000-2020): Santiago, São Paulo, México City, and New York City

To investigate the potential local health benefits of adopting greenhouse gas (GHG) mitigation policies, we develop scenarios of GHG mitigation for México City, México; Santiago, Chile; São Paulo, Brazil; and New York, New York, USA using air pollution health impact factors appropriate to each city. We estimate that the adoption of readily available technologies to lessen fossil fuel emissions over the next two decades in these four cities alone will reduce particulate matter and ozone and avoid approximately 64,000 (95% confidence interval [CI] 18,000-116,000) premature deaths (including infant deaths), 65,000 (95% CI 22,000-108,000) chronic bronchitis cases, and 46 million (95% CI 35-58 million) person-days of work loss or other restricted activity. These findings illustrate that GHG mitigation can provide considerable local air pollution-related public health benefits to countries that choose to abate GHG emissions by reducing fossil fuel combustion.

[Ambiguous sex: prevalence at birth in the maternity ward of the clinical hospital of the university of Chile]

BACKGROUND

Ambiguous sex has a great phenotypic variability and is a serious medical and social problem.

AIM

To study the prevalence of ambiguous sex among newborns.

MATERIAL AND METHODS

As part of the ECLAMC (Cooperative Latin American Study of Congenital Malformations) all newborns with malformations are registered and the next normal newborn is considered as a control.

RESULTS

50.253 births occurred (between 1982 and 1999) in the University of Chile Maternity Hospital. The rate of congenital malformations was 6.78% and the prevalence of ambiguous sex was 4.7 per 10.000 births. Affected children had a lower birth weight, lower gestational age and a lower maternal age than controls. The most frequent associated malformations were of the urinary (64%) and cardiovascular systems (60.7%). Thirty two percent of affected children had specific syndromes.

CONCLUSIONS

The prevalence of ambiguous sex in this study was 4.7 per 10.000 births, which is higher than that reported in the ECLAMC (1.9 per 10,000).

[Incidence of the cleft lip and palate in the University of Chile Maternity Hospital and in maternity Chilean participating in the Latin American Collaborative Study of Congenital Malformations (ECLAMC)]

BACKGROUND

ECLAMC is a registry, aimed to assess the incidence of congenital malformations, that started in 1967 and Chile incorporated to it in 1969.

AIM

To report the incidence of cleft lip/palate, updated to 1999 in the University of Chile Maternity Hospital and other Chilean hospitals participating in the ECLAMC.

PATIENTS AND METHODS

A review of the ECLAMC database that registers all births or stillbirths of more than 500 g.

RESULTS

The incidence of orofacial cleft, at the University of Chile Maternity Hospital, in the period 1991-1999 was 17.8 per 10,000 (12.6 for cleft lip and 5.2 for cleft palate). The incidence in the rest of participating hospitals was 12.04 and 4.6 respectively. Males had a higher incidence of cleft lip and 80% of children with cleft palate, had other malformations, most of them as part of a syndrome (13 and 18 trisomy, holoproscencephalia, Pierre Robin, Apert en EE syndromes, anencephaly etc). In three of 12 children with cleft lip but without cleft palate, there was a relative with the same malformation.

CONCLUSIONS

It is proposed that both entities, cleft lip with or without cleft palate and cleft palate without cleft lip, are two etiopathogenically different conditions.

[Study of 3 hypervariable loci in a mixed Chilean population]

BACKGROUND

Genetic markers are useful to study evolution parameters in populations and to determine kinship.

AIM

To characterize three short tandem repeat loci in a sample of Chilean subjects and compare them with Caucasian and Hispanic populations.

MATERIAL AND METHODS

Three hundred ninety three unrelated subjects that were sent for genetic studies from courts of justice, were studied. The loci FESFPS, F13A01 and vWA in blood samples, were typified amplifying DNA by polymerase chain reactions.

RESULTS

The three studied loci were highly polymorphic. F13A01 and FESFPS were in Hardy-Weinberg genetic equilibrium. A significant excess of heterozygotes was detected for vWA locus. There were no differences in allele frequencies, according to ethnic origins of last names. Allele frequencies for F13A01 and vWA loci were similar to those of Hispanic populations of Unites States and FESFPS loci was different.

CONCLUSIONS

All three loci had a high efficiency for genetic identification tests according to the estimated a priory exclusion probability.

[Disabling malformations in Chile. Latin American Cooperative Study of Congenital Malformations (ECLAMC), 1982-1997]

BACKGROUND

The ECLAMC (Estudio Colaborativo Latinoamericano de Malformaciones Congénitas) is an epidemiological surveillance program for congenital defects that operates in Chile since 1969.

AIM

To communicate the frequency of disabling congenital defects in Chile in the period 1982-1997.

MATERIAL AND METHODS

A review of the ECLAMC registry, choosing 12 congenital defects: amelia, limb amputations, limb reductions, arthrogryposis, hip luxation and subluxation, spina bifida, hydrocephaly, microcephaly, cephalocele, talipes equinovarus, Down syndrome and multiple abnormalities.

RESULTS

In the study period, 283,403 births occurred and 7,917 newborns were malformed (7,654 born alive and 263 stillbirths). The congenital defects prevalence rates appeared higher in Chile than in other Latin American countries, specially among stillbirths. Among the studied maternity hospitals, the Clinical Hospital of the University of Chile, showed the higher prevalence of congenital defects. Rancagua and the Navy Hospital in Valparaiso have a high frequency of Down syndrome. Global rates in Chile and in the rest of ECLAMC for specific defects, do not have significant differences, except for hip subluxation, that has a lower incidence in Chile.

CONCLUSIONS

The ECLAMC allows to have a good knowledge of the prevalence of congenital malformations in Latin America.

[Anorectal congenital malformations and their preferential associations. Experience of the Clinical Hospital of the University of Chile. Period 1979-1999]

BACKGROUND

Anorectal atresia is a relatively frequent malformation in the newborn. According to the Latin American Collaborative Study for Congenital Malformations (ECLAMC), its frequency is 4.1 per 10,000 born alive.

AIM

To determine the frequency of anorectal malformations at birth, and compare the figures with those of other maternity hospitals in Chile participating in ECLAMC, with the figures of the whole ECLAMC and with figures from other worldwide monitoring systems.

PATIENTS AND METHODS

All births occurred in the University of Chile Clinical Hospital between January 1979 and August 1999, were reviewed.

RESULTS

During the study period, 70,242 children were born, 4,486 had a malformation and 54 had an anorectal malformation (7.7 per 10,000 born alive). Fifty nine percent had other associated malformations (of the urinary tract in 42.5%, skeletal in 26% and cardiovascular in 18.5%). Five stillborn babies had other severe malformations. Twenty one children had a fistula. Forty three % were male, 39% female and 18% had ambiguous sex. When compared with normal controls, malformed newborns had a lower birth weight, lower gestational age and a higher mean maternal age, a higher frequency of metrorrhagia during the first trimester of pregnancy, a higher number of siblings with malformations and a higher degree of consanguinity among parents.

CONCLUSIONS

The participation of recessive genes in the etiology of anorectal malformations is suggested.

[Prevalence of congenital malformations at birth and associated factors in Easter Island, Chile (1988-1998)]

BACKGROUND

Consanguinity plays an important role in the genetic etiology of congenital malformations. In Easter Island the degree of consanguinity could be higher than in continental Chile. Therefore the study of the prevalence of congenital malformations in this island seems worthwhile.

AIM

To study the prevalence of congenital malformations at birth in Easter Island.

MATERIAL AND METHODS

A review of personal and family features of all children born alive between 1988 and 1998 in the Rapa Nui Hospital of Easter Island.

RESULTS

During the study period, 772 newborns were reviewed and 22 were found to have congenital malformations. Among the latter, birth weight fluctuated between 3001 and 4000 g and the male/female ratio was 0.54. No differences in maternal age between children with and without malformations was observed. Heart and circulatory malformations, hemangiomas and Down syndrome were the predominant malformations.

CONCLUSIONS

The prevalence of congenital malformations at birth in Easter Island is similar to that of continental Chile. No neural tube defects were detected in this sample.

[Paternity analysis using four DNA markers amplified by polymerase chain reaction]

BACKGROUND

DNA typing in forensic analysis is a useful tool to analyze paternity due to its high discrimination power.

AIM

To report the experience of Servicio Medico Legal in Santiago, resolving cases of dubious paternity.

SUBJECTS AND METHODS

Four highly polymorphic loci, amplified by polymerase chain reactions, were analyzed in 153 cases of uncertain paternity. The paternity index was calculated for each case.

RESULTS

The four genetic markers analyzed provided an exclusion probability of 0.933 for the general population in Santiago. Thirty-seven cases were excluded as parents. In 31 cases, the paternity index ranged from 19 to 100, considered as probable paternity and 77 cases had an index of over 100, considered as almost certain paternity. Eight cases had an index between 0.5 and 19, considered as inconclusive. All loci met Hardy-Weinberg expectations and their frequencies were similar to other data from people living in Santiago.

CONCLUSIONS

The use of these genetic markers proved to be very useful, reliable and with a high exclusion power for paternity analysis.

[Esophageal atresia and associated malformations]

BACKGROUND

Survival of newborns with esophageal atresia and tracheoesophageal fistula has increased in the last years.

AIM

To assess the prevalence of esophageal atresia and describe associated malformations in Chilean newborns.

MATERIAL AND METHODS

All births occurring between January 1983 and June 1998 were studied. All malformed children were registered and the next non malformed born child was considered as control.

RESULTS

During the study period, 50,965 births occurred and 3,336 malformed children were born. Eighteen (3 stillborn) had esophageal atresia with a rate of 3,53 per 10,000 born alive. Overall survival was 73%. Survival among children classified in Waterson groups A and B was 100% and 50% among those classified in group C. Seventy two percent had associated malformations, being congenital cardiopathies and skeletal malformations the most frequent. VACTERL association was found in 44% of children. All stillborn children had other severe malformations. When compared to controls, malformed children had a lower weight, a lower gestational age, their mothers had a higher age, a higher frequency of relatives with malformations and a higher frequency of maternal diseases during the first trimester of pregnancy.

CONCLUSIONS

The rate of esophageal atresia found in this study is similar to that reported in other Chilean obstetrical units as part of the Latin American Study of Congenital Malformations (ECLAMC).

Paternity analysis when the putative father is missing: first case in Chile

Genetic marker analysis is a powerful tool for solving paternity-related problems when the putative father is missing. This report describes the first time this approach was employed in Chile to solve such a problem. In the case presented, the alleged father was missing as a result of the political detentions that took place in Chile during 1973. It was not possible to obtain any biological sample from him because he was missing. Thus, the case was resolved by means of genetic marker analysis of the alleged father's close relatives.

Vernacularization as an intellectual and social bridge. The Catalan translations of Teodorico's Chirurgia and of Arnau de Vilanova's Regimen Sanitatis

This study analyzes the dissemination and readership of two medieval medical works in Catalan. Combining the use of diverse sources such as the manuscripts themselves, post-mortem inventories, and the prologues written by the translators, the study shows how the diffusion of these works exemplifies the two main audiences to which vernacular texts were addressed. These were, on the one hand, literate but not Latinate surgeons and other practitioners interested in the new medicine emanating from the emerging universities; and on the other, nobles and burghers interested in issues of health and disease and in natural philosophy in general. The framework for the study is the general process of consolidation of the new medical system which developed in late medieval Latin Europe.

[Congenital malformations in twins]

BACKGROUND

A higher prevalence of congenital malformations among twins than among single has been reported in the literature.

AIM

To study the incidence of congenital malformations in twins in the maternity hospital of the University of Chile in the period 1983-1997.

MATERIAL AND METHODS

As part of the Latin American Collaborative Study of Congenital Malformations, every newborn in the maternity hospital was examined by a neonatologist and congenital malformations were recorded in a special file.

RESULTS

In the study period there were 48.663 deliveries of single pregnancies and 448 deliveries of twin pregnancies, giving birth to 886 twins borns alive and 17 stillbirths (1.9% mortality). Of these, there were 423 twins, 17 triplets, a sextuple delivery and two siamese. Seven point one percent of twins born alive and 6.5% of single newborns had a congenital malformation. The prevalence of malformations in twins and single stillbirths was 35.2 and 17.2% respectively (p < 0.04). In four pairs and siamese newborns, malformations typical of monozygotic twins were present, such as an acardiac fetus with Trap sequence, a papyraceous fetus and two with hydroanencephaly. Twelve twins had malformations attributable to uterine compression.

CONCLUSIONS

This study did not find a higher frequency of malformations comparing twins with single babies born alive, but in stillbirths there was a significant difference between single and twin stillbirths (7.1% versus 35.2%, respectively, p < 0.05).

[Association between Kidd blood group and congenital malformations]

BACKGROUND

Since the discovery of blood groups, an association between these genetic polymorphisms and pathological phenotypes has been searched, looking for factors involved in the pathogenesis of diseases or biological population mechanisms that maintain these polymorphisms. In previous reports, we have described some associations between erythrocytic genetic marker segregation and the presence of congenital malformations.

AIM

To explore the association between Kidd blood group and congenital malformations.

PATIENTS AND METHODS

One hundred twenty two malformed newborns and their mothers and 136 normal newborns, seen at the Clinical Hospital of the University of Chile, were studied.

RESULTS

Kidd blood group segregation distortions were found among male malformed newborns, that were not present in normal newborns. Among mothers of both groups of newborns, a paucity of heterozygous for this system was found.

CONCLUSIONS

The association found between a blood group and congenital malformations, allows to state that malformed children have a different genetic background, when compared to normal children.

[Incidence of Down syndrome at a University Hospital Maternity of Chile. A 25-year record: 1972-1997]

BACKGROUND

The main function of ECLAMC (Latin American Congenital Malformations Collaborative Study) is to monitor congenital malformations in Latin American countries. Down syndrome, due to its medical and social importance, has received special concern.

AIM

To measure the rates of incidence of Down syndrome in an University hospital maternity and to compare demographic variables of children born with the syndrome and healthy children.

MATERIAL AND METHODS

Between 1990 and 1997, all children born with Down syndrome were registered, and the next healthy newborn of the same sex was considered as control. Also, using previous registers, the prevalence of newborns with Down syndrome and the mean maternal age from 1972 to 1997 were compared using regression equations.

RESULTS

During the 7 years study period, 53 Down syndrome patients were born (66% female, two stillbirths). Thirty percent had congenital heart disease, forty seven had a regular 21 trisomy, one had a Robertsonian translocation, two had mosaicism for 21 trisomy, one was 48, XXX + 21 and one was 48, XXY + 21. Compared to controls, these children had lower gestational age and birth weight, mean maternal and paternal ages were higher, previous abortions were more frequent and the intergenesic period more prolonged. From 1972 to 1997, both the birth rate of Down syndrome and mean maternal age increased significantly with slopes of 0.13 years of age per year and 0.05/1000 born alive per year, respectively. Comparing both rates, the prevalence rate of Down syndrome increased in 0.31 per 1000 born alive per year of increment in maternal age. Father's age had no influence on this prevalence.

CONCLUSIONS

In the period 1990-1197, a higher prevalence rate of Down syndrome than in previous periods in the same maternity, was found. The influence of maternal age on this prevalence was clearly established.