[Preliminary study of HLA markers in French Catalonia]. / Etude préliminaire des marqueurs HLA en Catalogne française.

Forty-two sets of parents and their two children, who had their origins for at least three generations in French Catalonia, were studied for HLA-A,B,C,DR and Bf alleles of the Properdine complement factors. Four haplotypes were observed to be in strong linkage disequilibrium (p less than 10(-3)): A1, Cw7, B8, DR3; Aw30 (Cw5), B18, BfF1, DR3; A1 (Cw6), B17; A29 or Aw23, Cw4, B12, BfF, DR7. The observed linkage disequilibria of these haplotypes in the French Catalonian population were compared with those already described among populations from the Basque country, the Toulouse area and Spanish Catalonia.

Occurrence of viruses in human stools in the Ahaggar (Alberia).

From October 1977 to May 1980, 243 stools collected in sedentary and semi-nomadic populations of the Ahaggar (Algerian Sahara) were examined using immunoelectronmicroscopy and tissue culture inoculation. Immunoelectronmicroscopy revealed the presence of rotaviruses in 8, coronaviruses in 26, adenoviruses in 5 and small round viruses in 4. Enteroviruses were isolated in tissue culture from 24 stools. Rotaviruses were present in the Ahaggar but were associated with little acute enteric disease. The high frequency of coronaviruses both in gastroenteritis patients and in patients without disease was surprising. The prevalence of enteroviruses in this hyperarid zone was similar to or higher than that found in noticeably more human countries. Further systematic bacterial, viral and parasitic examinations are required to clarify the role of the above viruses in the aetiology of gastroenteritis in this region.

Gc (vitamin D binding protein) subtype polymorphism and variants distribution among Saharan, Middle East, and African populations.

This article presents the results obtained by electrophoretic analysis of the group specific component polymorphism in more than 1,250 serum samples from populations living in the Sahara, the Middle East, and equatorial Africa. In addition to the alleles Gc1F and Gc1s, five variants, including one previously unknown, were found. The distribution of the alleles herein described permits speculation on exchanges and relations among the groups considered. The lowest frequencies of the gene Gc2 correspond to regions where sunlight is stronger. There is also a north-south gradient in the Gc1F gene frequency. This seems to parallel the gradient seen in skin pigmentation.

Study of red blood cell and serum enzymes in five Pyrenean communities and in a Basque population sample.

Until recently, no data on genetic polymorphisms in the populations living on the northern side of the Pyrenees have been available, except for the Basques. Several investigations were done lately on rural communities in various geographic zones in the Pyrenees from the eastern to the western part. In this paper, the results for the following enzyme polymorphisms are reported: acid phosphatases, AK, ADA, PGM1 and PGM2, 6PGD, NADH diaphorase, SOD, MDH, TGP, G6PD, C5 esterase (E2 locus), serum cholinesterase (E1 locus). Significant variation in gene frequencies was observed over the distinct geographic zones for the main polymorphic system. Furthermore, some rare alleles were found: a new G6PD variant (Luz-Saint-Sauveur), the presence of ADA3 and ADA5 alleles in two groups of the Central Pyrenees, a Dia2 gene among Basques and in the Pays de Sault, a high rate of Ea1 allele in the Basque group. The values obtained for the degree of heterozygosity are in agreement with the relative isolation of the different groups studied and confirm the importance of sociocultural factors in the evolution of the genetic background of rural communities in Europe.

Genetic variants of human glucose-6-phosphate dehydrogenase in a Saharian and Pygmy family.

In two African communities, inhabitants of a Western Sahara oasis and Bi-Aka Pygmies (Central Africa), a genetic study of the distribution of G6PD phenotypes has been undertaken. Obtained data show the existence in both groups of slow electrophoretic variants with no enzyme deficiency or moderately reduced activity. Biochemical characterization of G6PD types was performed. In the Saharian family in which inheritance pattern of mutant G6PD was investigated, two alleles were found, the Negroid marker GdA- and Gd+Madrona, segregating among the different members. In the Pygmy family the Gd+Ibadan-Austin gene was detected. The incidence of these mutations in the groups studied, a comparison with similar G6PD variants observed in other African populations and the geographic distribution of these slow molecules are discussed in this paper.

[Geographical survey of drepanocytemia: causes of its distribution in Africa south of Sahara (author's transl)]. / Géographie de la drépanocytose: les causes de sa répartition dans l'Afrique au sud du Sahara.

In Africa South of Sahara, HbS is distributed in east-west oriented belts, its frequency decreasing from equator to tropics. This singular feature results from interaction of various and complex phenomenons: apparition and diffusion of the mutation, role of malaria, climatic conditions.

Enzyme polymorphisms of Ideles populations (Ahaggar, Algeria) and the Iwellemeden Kel Kummer Twaregs (Menaka, Mali).

Surveys dealing with enzyme polymorphisms have recently been conducted in the Sahara. Results from two populations are reported here: 227 inhabitants of Ideles village (Ahaggar, Algeria); 285 nomads of a genetic isolate, the Kel Kummer Twareg tribe (Menaka, Mali). The four classical molecular variants of G6PD:A+, A-, B+, B-, are found in Ideles. The frequency of the G6PD A+ Negroid variant reaches 15% in Ideles and 7.7% among the Kel Kummer. However, gene frequencies will have to be recalculated after a study of the genetic transmission through families. The PGDC gene of 6PGD is especially frequent in the Kel Kummer where 10 'Canning' phenotypes have been observed. The PGM distribution of alleles at locus 1 in Ideles is the same as in the Mediterranean populations. The pa gene of acid phosphatase, relatively frequent in Ideles, has been excluded by drift from the Kel Kummer gene pool. AK and LDH enzymes have also been studied in both samples. The abnormal Ea1 mutation of serum pseudocholinesterase exists in Ideles and in the Kel Kummer as in other populations of the Sahara; the C5 esterase component was revealed by electrophoresis in 5% of the Kel Kummer people.