Sequence analysis of the CCG polymorphic region adjacent to the CAG triplet repeat of the HD gene in normal and HD chromosomes.

The CAG expansion responsible for Huntington's disease (HD) is followed by an adjacent polymorphic CCG repeat region which may interfere with a PCR based diagnosis. We have sequenced this region in 52 unrelated HD patients, from both normal and HD chromosomes. Fifty percent of the normal alleles were (CCG)7(CCT)2, 48% (CCG)10(CCT)2, and 2% (CCG)7(CCT)3.

Diagnosis of "sporadic" Huntington's disease.

The diagnosis of Huntington's disease (HD) in patients with progressive chorea and mental impairment, but without similarly affected relatives, remains uncertain and impedes genetic counseling. Twenty patients with suspected HD, but with no family history of the disease underwent molecular analysis of the CAG repeat in the IT15 gene for HD. Eighteen patients displayed the HD expanded allele and two had CAG repeats in the normal range.

Gender and age at onset in schizophrenia: impact of family history.

Objective: The 1-year prevalence of schizophrenia was studied in a limited geographical area of Reunion Island (Indian Ocean) to assess the impact of family history of schizophrenia on the well-known association between gender and age at onset.

Method: The population of schizophrenic patients meeting the DSM-III-R criteria for schizophrenia (N = 663) was identified and divided according to the presence of another schizophrenic patient among the first- and second-degree relatives.

Results: As previously reported, the median age at onset differed between the sexes: the males had an earlier onset (mean age = 27.

[Role of genetic epidemiology in the study of infectious diseases. The example of malaria].

Genetic epidemiology is a new tool for the study of malaria, with interesting incidence in the comprehension of host/parasite interrelations. The existence of a co-dominant major gene, with a mendelian transmission, controlling the levels of parasitemia has been found out. This allele has a frequency of 24% which means that about 6% of the population is predisposed to high parasitemias.

No evidence for genomic imprinting in liveborn Down syndrome patients.

Despite numerous studies, the clinical heterogeneity of Down syndrome has no explanation. The authors have attempted to investigate the role of genomic imprinting in the phenotype of liveborn Down syndrome patients. Hundred fifty eight patients were investigated for parental origin of the extra chromosome 21 with standard cytogenetic analyses and with DNA polymorphic markers.

[Mucoviscidosis: comparative analysis of epidemiological data of French and North American registries].

A national registry for cystic fibrosis was established in France in 1993. A questionnaire is sent once a year to different health care units. The first questionnaire was analyzed in 1992: 1,893 patients (53% males) were identified.

Busulfan-containing pre-transplant regimens for the treatment of solid tumors.

This study investigated the toxicity and efficacy of busulfan-containing pre-transplant regimens in patients with solid tumors. The majority of these patients were also treated on protocols involving two transplant courses aiming at further reducing tumor burden. Between October 1984 and November 1993, we treated 44 patients with recurrent breast cancer (n = 28), sarcoma (n = 10) or ovarian cancer (n = 6) with one of two busulfan-containing regimens.

Is Rett syndrome a chromosome breakage syndrome?

Lymphocytes from venous blood from 15 girls with Rett syndrome (RTS), 7 girls with RTS "forme fruste," and 46 unrelated control females were examined. All subjects had a normal karyotype using RHG and RTBG technique. The frequency of gaps and breaks was determined for each group.

Parental consanguinity as a cause of increased incidence of birth defects in a study of 131,760 consecutive births.

The risk for birth defects in the offspring of first cousin parents is substantially higher than in the offspring of non-consanguineous parents. As a general decline in the frequency of consanguineous marriages was observed in this century, one wonders whether consanguinity is still a factor in the appearance of birth defects in developed countries. Based on our registry of congenital anomalies, we think that the answer to this question is "yes.

Phenotypic variability in autosomal dominant cerebellar ataxia type I is unrelated to genetic heterogeneity.

Families with autosomal dominant cerebellar ataxia (ADCA), a heterogeneous group of diseases, were investigated prior to and during genetic linkage analysis. We report here on the clinical features of 122 affected individuals from 36 unrelated families with ADCA type I, the most common type. Our results indicate an anticipation expressed in a mean 9.

Huntington's disease in French families: CAG repeat expansion and linkage disequilibrium analysis.

The molecular defect causing Huntington's disease (HD) has been found as an expansion of CAG triplets in the 5' coding region of IT15 gene. In the 29 French families reported, the HD disease is due to the expansion of the CAG triplets region above 38 copies. The complete sequencing of 10 HD alleles PCR products allowed us to confirm that expansion is restricted to the CAG repeat region and does not extend to the adjacent CCG repeat region which is also present in the PCR product.

Epidemiological and clinical study of sickle cell disease in France, French Guiana and Algeria.

The main clinical and haematological features of sickle cell patients were compared in 618 French, 50 Guianese and 87 Algerian patients. In homozygous sickle cell patients, the proportion of icteric subjects rises with age in all centres; the prevalence of splenomegaly reaches a peak in children from 1 to 5 years and then decreases; jaundice and splenomegaly are more often noted in Algerian and Guianese than French patients. The prevalence of painful crisis is comparable in the 3 centres.

Genetic variation in transforming growth factor alpha: possible association of BamHI polymorphism with bilateral sporadic cleft lip and palate.

Non-syndromic cleft lip with or without cleft palate (CL/P) is one of the most common birth defects affecting 1/1000 Caucasians. Genetic factors are thought to contribute to the development of this disorder. A significant association between two restriction fragment length polymorphisms, the TGF alpha TaqI 2.

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.

Transforming growth factor-alpha: characterization of the BamHI, RsaI, and TaqI polymorphic regions.

We have characterized the nature of structural alleles of the transforming growth factor-alpha (TGF alpha) locus by restriction-enzyme digestion with BamHI, RsaI, and TaqI. The BamHI polymorphic site is located within exon VI, which codes for the 3' untranslated region. The two BamHI alleles differ by a single point mutation at the restriction site.

Risk factors of malaria infection during pregnancy in Burkina Faso: suggestion of a genetic influence.

A cohort of 570 untreated pregnant women from Burkina Faso was studied to assess the influence of epidemiologic factors on malaria infection, which was quantified as the mean of serial, season-adjusted parasitemia measurements (mean parasite density [MPD]) carried out during the last five months of gestation. A significant effect of the area of maternal residence on the MPD was found (P < 0.003) and was probably due to geographic differences in mosquito transmission conditions.

[Collection of familial data in pharmacogenetics. Methodological problems].

The purpose of this paper is to show the problems with family data collection in a pharmacogenetic study, the aim of which was to study the genetic polymorphism of inducibility of cytochromes P4501A by polycyclic aromatic hydrocarbon (PAH). Data were collected from 76 smoker nuclear families (315 volunteers). A caffeine test, a blood sample and answers to a questionnaire were obtained from each healthy volunteer.