Mitochondrial DNA in Basque descendants from the city of Trinidad, Uruguay: Uruguayan- or Basque-like population?

Like other countries in the Americas, during its colonization Uruguay was the recipient of immigrants from several ethnic groups from Europe, as well as of enslaved Africans. After its independence in 1830, Basques were the first group of Europeans to arrive in the country. In this paper, we aim to contribute to the understanding of the process of integration of these migratory waves into the Uruguayan society. For that purpose, individuals of Basque origin from the city of Trinidad, Uruguay, were chosen to participate in this study. Particularly, we wanted to determine if Basque descendants in Uruguay remained relatively isolated or if they mixed with other ethnic groups. Mitochondrial DNA (mtDNA) of 60 self-identified Basque descendants, taken from a larger sample of subjects with Basque ancestors, was analyzed. The origin of mtDNA haplogroups was 77.8% European, 20.4% Amerindian, and 1.8% African, showing similar frequencies to other Uruguayan regions. Very few sequences showed a clear Basque origin, although other sources such as the Canary Islands are likely. Moreover, genetic distances clearly show that Basque descendants are genetically closer to other Uruguayan groups than to European populations, including Basques. It is possible to conclude that Basques and their descendants in the region of Trinidad did not remain isolated and that their marriage behavior was similar to that of other Uruguayan populations. However, to have a more accurate picture of the way Basques intermarried with other populations in Uruguay, new analyses are needed that take into account paternal lineages as well as biparental genetic markers.

Consanguinity in two Uruguayan cities: historical evolution and characteristics (1800--1994).

BACKGROUND: Information about consanguinity in Uruguay is scarce and limited to the end of the 20th century. AIM: To determine the frequency and characteristics of consanguineous marriages, as well as chronological trends, in two Uruguayan cities over almost two centuries. SUBJECTS AND METHODS: We analysed 28,393 Roman Catholic Church marriage records and Diocesan consanguinity dispensations belonging to the cities of Melo (Northeast), and Montevideo (South), for the period 1800--1994. RESULTS: 633 (2.23%) marriages were consanguineous. Among them, first cousin marriages were the most common (58.8% of all consanguineous marriages, including double consanguineous), especially those where the bride and groom were related through their maternal side. During the first decades of the 19th century both regions showed low levels of consanguinity. Consanguinity reached its maximum during the mid-1800s and decreased significantly throughout the 20th century. The overall mean coefficients of inbreeding were moderate in both cases, being greater in the Northeast (alpha=0.00165) than in the South (alpha = 0.00089). CONCLUSIONS: The low level of consanguinity as well as the structure of consanguineous marriages (distribution by degrees) is similar to that found in other southern South American countries. Temporal trends are similar to those found in industrialized regions in Europe, with maximum inbreeding levels during the middle-late 19th century; however, the clear predominance of first cousin unions, differs from most of the data for European countries. Small differences between the two cities can be related to diverse facts, such as socio-economic conditions, ethnic origin, immigration, and sampling.

HLA-A, -B, -DR en receptores de trasplante de médula ósea en Uruguay: Sistema Nacional de registro, tipificación y búsqueda de donantes de médula ósea y progenitores hematopoyéticos (SINDOME) / National System of Recording, Typification and Searching for spina cord donors and hematopoietic progenitors (SINDOME)

Uruguay posee un sistema solidario de financiación de trasplante a través del Fondo Nacional de Recursos y del banco Nacional de Órganos y tejidos (BNOT). En el trasplante alogénico de médula ósea la compatibilidad HLA es una barrera biológica importante. Las frecuencias alélicas y haplotípicas HLA son utilizadas para determinar la probabilidad de encontrar un donante con un fenotipo particular HLA y para predecir el efecto de diversos esquemas de adjudicación basados en la compatibilidad en este sistema. El Laboratorio de Inmunogenética e Histocompatibilidad tipifica a todos los receptores y donantes del país. Se ha iniciado un programa cuyo objetivo central es organizar un sistema de registro, tipificación y búsqueda de donantes no relacionados a nivel nacional (SINDOME). Objetivos: analizar los receptores tipificados para trasplante de médula ósea (TMO) alogénico en nuestro servicio en el período enero 1997 - mayo 2002, y caracterizar la constitución genética del sistema HLA para 298 receptores. Material y método: en el lapso indicado se estudiaron 346 receptores y 1.083 donantes. Se realizó la tipificación HLA clase I por reacción de microlinfocitotoxicidad con anticuerpos monoclonales y la reversa, con nivel de resolución intermedio-alta. Se estimaron las frecuencias alélicas y haplotípicas en una muestra de 298 receptores. Resultados: de los 346 receptores de TMO estudiados en el marco del SINDOME, 58 por ciento es menor de 30 años. La relación donante-receptor fue de 3,13 pero sólo el 45 por ciento de los candidatos a trasplante tuvo un donante histocompatible. En el análisis del polimorfismo de HLA-A, -B, -DR en la muestra de 298 receptores se encontró que los alelos más prevalentes fueron A2 (28,97 por ciento), B35 812,49 por ciento) y DR04 (15,24 por ciento). Sólo para el locus HLA-DRB1 la desviación del equilibrio de Hardy-Weinberg fue altamente significativa. Los haplotipos más comunes fueron A2-B51 y A2-B7 para HLA-A, -B, A2-DR11 y A2-DR04 para HLA-A -DRB1, y el haplotipo B8-DR03 para HLA-B -DR. De los Haplotipos HLA-A -B -DRB1, HLA-A1 -B8 -DR03 y HLA-A2 -B51 -DR13 fueron los más frecuentes. Conclusión: nuestros resultados demuestran que el sistema HLA presenta una considerable heterogeneidad, con un enorme polimorfismo y una amplia distribución de haplotipos. La posibilidad de encontrar donantes compatibles para un subgrupo de jóvenes con enfermedades malignas sin donantes familiares es muy baja. (AU)

Association between diabetes type 1 and DQB1 alleles in a case-control study conducted in Montevideo, Uruguay

We studied HLA DQB1 allele frequencies and the relative risk (RR) of various genotypes in 72 type 1 diabetic patients and 40 control individuals in Uruguay. This is a tri-racial (Caucasian, Black and Indo-American) mixed population. The products of the polymerase chain reaction amplifications were hybridized with oligonucleotides by allele-specific oligonucleotide reverse or dot blot methods. Significant differences between these two groups were observed only for allele DQB1*0302 (35, RR = 7.34, P<0.001). The frequency of the alleles carrying a non-aspartic acid residue at position 57 was significantly higher in the diabetic patients (85 vs 53, P<0.001). In contrast, the frequency of Asp alleles was negatively associated with type 1 diabetes (RR = 0.20, P<0.001). The genotype DQB1*0302/DQB1*0201 (33, RR = 5.41, P<0.05) was positively associated with this disease. The genotype frequencies associated with type 1 diabetes in our population were significantly different from what is known for Caucasian and Black populations as well as compared with another admixed population, from Chile

[Erythrocyte glutathione reductase in pregnant women with hemoglobin AA and AS]. / La glutatión reductasa eritrocitaria en gestantes con hemoglobina AA y AS.

PURPOSE: To evaluate the catalytic activity of the red cell enzyme, glutathione reductase (GR) in pregnant women with Hb AS and with Hb AA, and in a group of non-pregnant women with Hb AA, as well as the relationship of GR deficiency with Hb S. PATIENTS AND METHODS: The catalytic activity was determined in presence and absence of FAD by means of a modified Long and Carson technique. 59 pregnant women with AS and 33 with AA phenotypes were studied. RESULTS: Differences were found in the enzyme's catalytic activity with and without FAD, both in pregnant women with Hb AS (mean values 37.17 nka/g y Hb in whites and 42.84 nkat/g HS in afro people) and in those with Hb AA, and also in non-pregnant women with Hb AA. A high frequency of GR deficiency was found in all groups due to an insufficient riboflavin supply in diet. CONCLUSION: A correlation between GR deficiency and Hb S could not be demonstrated. The coefficient of activity of red cell GR shows a tendency to increase in pregnancy due to certain riboflavin deficit of diet.

[Electrophoresis of 1,149 samples of umbilical cord blood and assessment of the heterogeneity of the relationship between gamma G and gamma A chains of fetal hemoglobin]. / Electroforesis de 1.149 muestras de sangre de cordón umbilical y evaluación de la heterogeneidad de la relación entre cadenas gamma G y gamma A de la hemoglobina fetal.

A total number of 1,149 specimens of cord-blood were subjected to cellulose acetate gel electrophoresis in order to estimate the incidence of haemoglobinopathies in newborn infants (NBI). It was found that 4.37% of black NBI and 0.54% of white NBI were AS carriers. Those samples with HbS or HbC were verified by means of agar-citrate electrophoresis at pH 6.2. Haemoglobin Bart was commonest in black (3.1%) than in white (0.4%) NBI. A slow haemoglobin variant was found with an alpha-chain mutation. The concentration of gamma G was estimated by separation of gamma G and gamma A chains with polyacrylamide gel electrophoresis, and it ranged between 52% and 94%, which could be attributed to the fact that the shift from HbF to HbA is not simultaneous in all the red-cell population.