Familial aggregation of Leishmania chagasi infection in northeastern Brazil.

A sample of 1,604 individuals belonging to 243 nuclear families from an endemic area of visceral leishmaniasis (Jacobina, Bahia State, Brazil) was studied to disclose the intrafamilial pattern of infection. Significant father to offspring, mother to offspring, and sibling to sibling associations, in contrast a with nonsignificant father to mother association, clearly indicate a familial aggregation of the infection, with a strong suggestion of at least partial genetic involvement.

Autosomal recessive malformation syndrome with minor manifestation in the heterozygotes: a preliminary report of a possible new syndrome.

We describe 3 patients with a new malformation syndrome in 2 sibships in a large kindred from Bahia, Brazil. The parents in both sibships are consanguineous. The syndrome is characterized by malformations of the face, ears, hands and feet, plus mixed deafness and pseudopapilledema. Fifty-four relatives were examined clinically and scored by the number of anomalies. A control sample of 54 individuals was equally examined. The distribution of the number of anomalies per individual (score) is bimodal in the relatives of the patients but unimodal in the control individuals. Detection of heterozygotes was based on the score distribution.

Null allele in a human polymorphism restricted to the placenta: call for a search.

The identification of a null allele in a human genetic system restricted to the placenta is a great challenge for two reasons: the impossibility of carrying out family studies and the unviability of sample recollections because the placenta itself is a disposable universe. Thus, in addition to reporting the finding of a null phenotype of placental alkaline phosphatase in a dark mulatto newborn from a black mixed population of Bahia, Brazil, here we present other evidence for the presence of the ALPP*Q0 allele with considerably high frequency in this population.

Delta-aminolevulinate dehydrase (ALAD) polymorphism in mixed Brazilians from the State of Bahia.

Electrophoretic polymorphism of delta-aminolevulinate dehydrase (ALAD) was studied on 519 individuals from Bahia, Brazil. Subjective assessment of Black ancestries carried out in a five point visual scale (White, Light Mulatto, Medium Mulatto, Dark Mulatto and Black) allowed to show that the ALAD*2 allele frequency decreases from 8% in Whites to 0% in Blacks. These findings agree with previous reports of ALAD in Africans, American Indians and Spanish. The powerful peculiarity of the ALAD system in assessing racial admixture is stressed.

Factor VIII:C, ABO blood groups, and black admixture in a Brazilian sample.

The effects of ABO blood groups and black admixture on the level of factor VIII:C are studied in healthy adults from Salvador, Bahia, Brazil. A racially mixed sample of 125 males was selected as follows: 25 whites, 25 light mulattoes, 25 medium mulattoes, 25 dark mulattoes, and 25 blacks. Levels of both factor VIII:C and K-PTT followed normal distributions. O blood group subjects showed lower factor VIII:C levels (110.20 +/- 30.76%) than non-O blood group members (135.24 +/- 31.42%) (t123 = 4.47; p less than 0.0001) and higher K-PTT levels (37.69 +/- 4.57 s) than non-O blood group subjects (35.25 +/- 3.82 s) (t123 = 3.24; p less than 0.01). By holding ABO blood type constant, there is a significant racial effect (white) on lowering the factor VIII:C level within both blood group O (t43 = 2.23; p less than 0.05) and non-O (t36 = 3.44; p less than 0.002). There is no interaction effect of race and blood group (F = 0.19; p greater than 0.6) on the factor VIII:C levels.

PGM3 polymorphism in human placenta samples from Bahia, Brazil.

PGM3 polymorphism was studied in 301 placenta samples from the Negroid population of Northeastern Brazil. The following gene frequencies were encountered: PGM3*1 = 0.545 and PGM3*2 = 0.455. They lie between European and African gene frequencies. The prevalent Black and White admixture of Northeastern Brazil populations fits well with the observed gene frequencies. Two samples exhibited variant electrophoretic patterns.

Frequencies of atypical serum cholinesterase in a mixed population of northeastern Brazil.

Frequencies of the CHE1*A allele were estimated in 84 Whites and 772 Negroids from a random sample of Salvador, Bahia. The overall frequency of this gene in Negroids was estimated as 0.842 +/- 0.233%. This indicates that this sample presents around 50 +/- 17% of White admixture and that the estimate of the risk of developing prolonged apnoea in individuals submitted to suxamethonium is around 0.035%, that is about 1 out of 2,900.

Multivariate study of birth weight and maternal heterozygosity for sickle cell anemia in Bahia, Brazil.

A series of 1,008 newborns of indigent mothers from a mixed Brazilian population was studied with respect to the effect on birth weight of heterozygosity for sickle cell anemia, fetal sex, maternal age, parity, smoking, alcohol consumption and black admixture. Maternal heterozygosity for sickle cell anemia had no measurable effect on birth weight. Significant effects were found for male sex (increase) and smoking (decrease).

Spread and diversity of human populations in Bahia, Brazil.

PIP: Data from surnames and racial subgroups were obtained in 60 localities to reconstruct the history of population spread and mixing over the state of Bahia, Brazil. Using the historically significant location of Cachoeira and Sao Felix as central points, the sampled localities were distributed along 7 main paved roads. 20% of the elementary school children were selected, but only the surnames of 12,872 boys were used in the analysis. The following parameters were estimated for each of the localities: black phenotype index (BPI), which is the proportion of 3 racial classifications determined by gene frequency analysis; black cultural index (BCI) determined by the frequency of devotional surnames; and indian cultural index (ICI) determined by the frequency of animal-plant surnames; and the isolated frequency of the surname Santos. The results of regression analysis indicate a negative association between BPI and BCI and the distance from Cachoeira-Sao Felix. Although not significant, ICI increases slightly with increased distance from Cachoeira-Sao Felix. The isolated frequency of the surname Santos is associated with the BCI but does not decrease significantly with distance from Cachoeira-Sao Felix. Construction of a map characterizing each of the 60 localities by its most representative racial admixture confirms the analysis and reveals the spread of blacks toward 4 cardinal points. A review of the historical background of the state explains the migration of blacks as related to the needs for slave labor during the development of gold mining and cocoa and sugar cultivation. The higher concentrations of indian admixtures farther from Cachoeira-Sao Felix reflects their retreat to survive the incoming foreign settlers. Given the strong link between the observed diversity in the population and major historical events, it is suggested that historical reconstruction of a population be an initial step before undertaking sampling for gene frequency analysis.^ieng

Joint mobility in children: a population study.

The mobility of five joint pairs ( metacarpophalangeal, wrist, elbow, knee and ankle) was investigated in 3,000 mixed school children of Bahia, Brazil. A sampling method was designed to assure an equal number of fifty children in the smallest classes, when age, race and sex were held constant. Race was classified in five subgroups to assess the proportion of Black admixture. Multiple regression was carried out to analyze the data. The results showed a consistent effect of age on decreasing joint mobility, The effect of race was also on decreasing mobility of wrist, elbow and ankle; the darker the child, the less the joint mobility. However, the effect of sex showed no general consistency; for wrist, elbow and knee the girls had more mobility than the boys; for the ankle the boys had more mobility than the girls; and the metacarpophalangeal joint there was no sex difference. The complexity of multicausal effects on joint mobility are discussed considering the simultaneous interplay of biological and environmental actions.

Generalized joint hypermobility and black admixture in school children of Bahia, Brazil.

Joint hypermobility was investigated in a sample of 3,000 school children, ages 6--7 years, in Bahia, Brazil. A sampling method was designed to assure an equal number of 50 children in the smallest size classes, when age, race, and sex were held constant. Race was classified in five subgroups to assess the proportion of black admixture. The overall frequency of generalized joint hypermobility was 2.3%. The darker the children the lower the frequency of affected children. However, this racial effect was also associated with age: The highest frequency of generalized joint hypermobility was among the youngest and less black mixed children, whereas among the oldest and darker children there was no case of joint hypermobility.