Any migration results in the transfer of normal and pathological genes from one population to another. The frequency of pathological genes may vary according to the population, sickle cell anaemia, for instance, being frequent in Africa and cystic fibrosis in Europe. It follows that the hereditary pathology of migrants is not the same as that of the host population, at least during the immediate post-migration years; subsequently, all depends on the degree of cross-breeding. In epidemiological genetics the study of the frequency of some diseases in the original population, among migrants and in the host population enables the effects of genes and environment on the aetiology of these diseases to be investigated.

Genetic Diseases, Inborn↗

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Comparability and precision of serum PCB measurements.

The 95% prediction interval for single measurements of serum "Aroclor" reported by a reputable commercial analyst was found to be approximately +/- 42%. The geometric mean serum PCB levels in a population of capacitor workers who had formerly had direct exposure to the commercial PCBs--Aroclors 1016, 1242, and 1254-were found to be alternatively reportable as 1905 ppb minimum initial PCBs (as calculated from most persistent peaks present); 1093 ppb non-overlapping analytical "Aroclor" levels (as calculated by the conventional sum-of-the-peak-heights method); 303 ppb total PCBs actually present; or 19 ppb "human PCB" (as calculated by the NHMP procedure). The broad spread in reportable values was relatable to the PCB isomer distribution and clearance patterns in the occupationally exposed population.

Adult↗

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Ethnic difference in duration of pregnancy.

It is suggested that the observed difference in duration of pregnancy between Blacks and Whites is partly physiological since it is not entirely explained by social inequities alone. This study compares women with well-defined gestational periods seeking attention at the Antoine Béclère Maternity Clinic. Group A consists of French women of European ancestry, Group B, those born in the French Antilles of mixed ancestry, and Group C black African women with insignificant European admixture. When compared to Group A, within each socio-economic class, group B and C have shorter gestational periods. These differences persist after adjustment for socio-economic variables, so that other explanations should be considered, specifically genetic determinants.

Africa↗

PubMedDate not supplied

Population genetics of abnormal haemoglobins in Burkina Faso, west Africa.

The gene frequencies of haemoglobin A (HbA), HbS and HbC were studied in Burkina-Faso (BF) and in a neighbouring region of Niger, Ayorou. The frequency of HbS was higher in the Sahel region, (northern part of BF and Ayorou) than in the Savanna region. The reverse was true for the HbC gene. The major findings of this study are: (a) confirmation of a peak of HbC gene frequency in the central region of BF (Mossi plateau); (b) a possible negative correlation between the frequencies of HbS and HbC-Cavalli-Sforza and Bodmer have observed that this correlation is at a significantly different level from that expected because of the allelic relationship between HbS and HbC; (c) comparison with the data collected by Livingstone shows a modification in the fitness of the different genotypes in the last thirty years: AS individuals have a lower and AA and SS a higher fitness. Our data favour a partial selection relaxation in this region.

Burkina Faso↗

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Genetic predisposition to West syndrome.

To determine the recurrence risk of West syndrome (WS), we studied the familial antecedents of consecutively referred patients. Among siblings, there was an increased incidence of WS but not of febrile convulsions. Familial incidence of epilepsy was intermediate between the epileptic and nonepileptic control groups. When cases resulting from a genetically determined disease were excluded, incidence of epilepsy among siblings was similar to that in normal controls. Five of the 11 familial cases of WS were due to an identifiable cause: twin pregnancy, tuberous sclerosis, and recurrent maternal toxemia. In 4 of the remaining families, the clinical picture included spasms, erratic myoclonus, and postnatal microcephaly, suggestive of a previously unidentifiable progressive encephalopathy. Therefore, when identifiable familial diseases were excluded, the recurrence risk was < 1%.

Child, Preschool↗

PubMedDate not supplied

Glucose-6-phosphate dehydrogenase deficiency and homozygous sickle cell disease in Congo.

G6PD genotypes were determined in Brazzaville (Congo) on 188 HbSS patients (109 females, 79 males) and 210 controls (115 females and 95 males) with HbAA. DNA samples were analyzed by the polymerase chain reaction (PCR). The frequencies of G6PD B, A+ and A- alleles were 56.9, 20.8 and, 22.2% in the patients versus 56.3, 21.2 and, 22.5% in the controls, respectively. The prevalence of G6PD genotypes in HbSS did not differ (p > 0.05) from that found in the controls. Prevalence of G6PD deficiency did not change when patients were stratified by age, suggesting that there is no advantage of the association of G6PD deficiency with HbSS. Red blood cell count, mean corpuscular volume and mean corpuscular hemoglobin were not modified by the G6PD genotypes, while Hb level was lower in HbSS with G6PD A-. Our study suggests that in Congo, G6PD deficiency does not offer any biological advantage to sicklers.

Adolescent↗

PubMedDate not supplied

alpha-thalassemia in Bantu population from Congo-Brazzaville: its interaction with sickle cell anemia.

Deletional alpha(+)-thalassemia (-alpha(3.7)) was investigated in four groups of unrelated individuals from the Bantu population (newborns, normal adults, sickle cells trait carriers, sickle cell anemia patients) of Brazzaville, Congo. The frequency of the (-alpha(3.7)) chromosome was similar between newborns (f = 0.40) and adult subjects (f = 0.36), and between sicklers and nonsickler subjects. The frequency of the (-alpha(3.7)) chromosome in sickle cell anemia patients (SS patients) did not change when age was stratified. The hematological characteristics of SS patients with (-alpha/alphaalpha, -alpha/-alpha) and without (alphaalpha/alphaalpha) alpha(+)-thalassemia were similar to those reported in Jamaican and US sickle cell anemia patients. alpha(+)-Thalassemia had an effect on the percentage of hemoglobin S in sickle cell trait carriers. Thus, the high frequency of alpha(+)-thalassemia in the Congolese population presumably results from this disorder having a selective advantage favoring survival. However, the frequency of alpha(+)-thalassemia was not affected by age. Although in this selective tropical environment, alpha(+)-thalassemia as elsewhere markedly affects the hematological characteristics of sickle cell anemia patients, however our data provide no evidence that alpha(+)-thalassemia increases survival of SS patients.

Adolescent↗

PubMedDate not supplied

Cystic fibrosis mutations: report from the French Registry. The Clinical Centers of the CF.

Data from 2,666 patients with cystic fibrosis (CF) born in France, submitted during the period of 1992-1996 to the French registry for CF, were used to describe the different mutations, their frequency and their regional distribution. A total of 5,332 CF chromosomes have been analyzed, demonstrating 229 different mutations and accounting for 87% of CF genes in the French population. DeltaF508 is the most common mutation at 67.9% of CF mutations, followed by G542X (2.5%), N1303K (2.0%), 1717-1G-->A (1.2%), R553X (0.8%) and G551D (0.7%). The data show a clear geographical variation in the distribution of many of the mutations. Given the geographical heterogeneity of these mutations, carrier screening does not appear to be feasible in most French regions.

Cystic Fibrosis↗

PubMedDate not supplied

[Genetic epidemiology and psychiatry (I): scope and limitations of familial studies. Case of panic disorder].

Genetics epidemiology shed new light on multifactorial disorders for which genes are partly involved, for example on numerous psychiatric diseases. Nevertheless, each epidemiological technic has it's caracteristics and limitations. This review discuss the impact of aggregation studies, on the bases of an example, namely all aggregation studies on panic disorder. We detected through Medline thirteen studies, comparing 3,700 relatives of 780 probands affected with panic disorder, with 3,400 relatives of 720 unaffected controls. It is computed that relatives of patients with panic disorder have an increased risk (10.7%) for panic disorder than relatives of controls (1.4%), relatives from affected probands having a high relative risk (6.8) for panic disorder according to the meta-analysis. On the basis of these 13 aggregation studies, there is an important attribuable risk (78.3%) of "having a familial history of panic disorder" in the risk for panic disorder. Furthermore, the estimated heritability is 73% (73% of the total variance would be explained by additive genetic effects), if Reich's conditions are fulfilled for a valid estimation of the heritability on the basis of aggregation families. These studies can also be used to highlight the variability of expression according to gender, to show the relevance of quantitative approaches (versus the qualitative approach which is nearly systematically used), to underline the informations raised by experimental technics (such as panic disorder induced by lactate), and to raise the potential existence of phenocopies. Lastly, aggregation studies on panic disorder can help to understand the high comorbidity of this disorder, with other anxiety disorders and mood disorder.

Female↗

PubMedDate not supplied

Adult day care: reappraisal, austerity, opportunity of the non-profit role.

Explore the source record for details and available documents.

Aged↗

PubMedDate not supplied

[Familial forms of schizophrenia. Cytogenetic study].

As a preliminary step in the search for chromosomal location of a susceptibility gene predisposing to schizophrenia, cytogenetic screening of patients might be useful. Search for chromosomal aberrations has successfully directed and accelerated the identification of several disease genes, such as the Duchenne muscular dystrophy gene, retinoblastoma, Burkitt's lymphoma and chronic myeloïd leukemia. Although karyotypes abnormalities do not account for a large portion of cases of Schizophrenia, the two candidate regions predisposing to this disease resulted from observation of chromosomal abnormalities. First, the identification of a partial trisomy of the 5q11-q13 region (Basset et al., 1988) led Sherrington et al. (1988) to report a positive linkage with markers localized on the long arm of chromosome 5, which has not yet been replicated (Kauffman et al., 1989; Kennedy et al., 1988; St Clair et al., 1989). Second, on the basis of frequent cytogenetic abnormalities of the sex chromosome (DeLisi, 1985) in addition to epidemiological observations, Crow (1988) suggested that there could be a locus for psychosis within the pseudoautosomal region, a data which has been recently confirmed (Collinge et al., 1991). With the hypothesis that such aberrations could be more frequent among schizophrenics who have at least one affected first-degree relative, we undertook cytogenetic screening on a sample recruited from consecutive psychiatric admissions to a Psychiatric facility (Hôpital Saint Paul) involving patients living in a limited geographical area on the island of La Réunion, a French Department in the Indian Ocean.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Aberrations↗

PubMedDate not supplied

[Incidence of congenital malformations at birth in a series of maternity patients of Guadeloupe].

A study of 8,142 live and still-born babies was carried out from July 1979 to February 1983 in Guadeloupe (French West Indies). The total incidence of malformations detected at birth was 1.71% (minor malformations such as polydactyly being very frequent in this population were excluded). Among the malformed children, 25% had multiple malformations and 17% were still-born. Two types of malformations seem to be particularly frequent: those of the central nervous system (3.8%) and of the digestive tract (2.45%). The malformed group differs in birth-weight and size, in still-birth rate and in the incidence of obstetrical history.

Abnormalities, Multiple↗

PubMedDate not supplied

[Ethnic variation of the duration of gestation].

This study compares the durations of gestation of 6,885 West Indian women who delivered in Fort-de-France, with 11,818 Metropolitan, 257 West Indian and 110 African women whose deliveries took place in Clamart (France). Mean duration of pregnancy was 4/10 of a week shorter: i.e. 3 days, for West Indians. There was no difference between West Indians giving birth in Fort-de-France as opposed to those giving birth in Clamart. Duration of pregnancy was shortest for Africans as compared with West Indians and Metropolitans. These differences were statistically significant. At Clamart, despite standardization allowing for maternal ages, parity and socio-economic status, mean differences and their statistical significance remained.

Africa↗