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C Ferec

Publications and source records attributed to C Ferec.

At least 55 records · Page 3Linked to original sources
PubMed1998

Assessment of activated protein C resistance using a new and rapid venom-based test: STA Staclot APC-R.

Activated protein C (APC) resistance is related to a single point mutation in the factor V gene (FV:Q506) and appears to be the most common inherited risk factor for venous thromboembolism. A reliable screening test is therefore useful. We aimed to evaluate a new APC resistance test, on the basis of the procoagulant activity present in one snake venom of a crotalidae family: STA Staclot APC-R. We studied 36 consecutive patients with an acute deep venous thrombosis (DVT) confirmed by compression ultrasonography and carrying the FV:Q506 allele, assessed by DNA analysis, 103 of their family members and 35 consecutive patients with a proven DVT but who did not carry the FV:Q506 allele. Blood samples were collected within 24 h of admission for the DVT cases and on the day of medical registration for the family members. Tests were performed blind. The STA Staclot APC-R test, using a cut-off value of 0.80, had an overall sensitivity of 100% (95% CI, 95-100) and a specificity of 98.8% (95% CI, 92.0-99.6). An acute thrombosis process did not influence the performance of the test. We conclude that this test is easy and rapid to perform in every day practice and fulfills the criteria for a screening test.

Adult↗
PubMed1998

Cystic fibrosis screening: a fetus with hyperechogenic bowel may be the index case.

BACKGROUND: The potential of hyperechogenic fetal bowel to act as a hallmark for prenatal cystic fibrosis screening in the general population is controversial. METHODS: Our goal was to evaluate the incidence of cystic fibrosis in 209 fetuses with hyperechogenic bowel diagnosed at routine ultrasonography and with no family history of cystic fibrosis. The diagnosis of cystic fibrosis was based on prenatal screening for the eight mutations most frequently observed in France (deltaF508, deltaI507, 1717-1G-->A, G542X, G551D, R553X, W1282X, N1303K) and at postnatal follow up. RESULTS: The overall incidence of cystic fibrosis was 7/209 (3.3%) which is 84 times the estimated risk of CF in the general population (112500). Of these seven cases, six were diagnosed prenatally based on DNA analysis (deltaF508/deltaF508, n=5; deltaF508/G542X, n=1). One case in which only one mutation had been recognised was diagnosed clinically after birth (deltaF508/unidentified mutation). Of the seven cases, none was diagnosed at 16-19 weeks, four at 16-24 weeks, and three after this. The incidence of heterozygous fetuses (15/209, 7%) was not significantly higher than the 5% expected in the general population. The mutations involved in these heterozygous cases were deltaF508 (n=13), G542X (n=1), and G551D (n=1). CONCLUSIONS: Screening for cystic fibrosis should be offered to families in which fetal hyperechogenic bowel is diagnosed at routine ultrasonography. This underlines the need to review genetic counselling in this situation where the fetus is the index case for a genetic disease.

Cystic Fibrosis↗
PubMed1997

Phenotype-genotype correlation in haemochromatosis subjects.

Haemochromatosis is a common autosomal recessive genetic disorder of iron metabolism. A candidate gene was recently identified (HLA-H) and two amino acid substitutions (C282Y and H63D) were characterized. Haemochromatosis probands (n = 478) from Brittany were selected from their iron status markers, primarily serum iron, serum ferritin and transferrin saturation. We investigated the relationships between haemochromatosis phenotype and genotypes at the HLA-H locus and surrounding markers. As already reported, we observed that the C282Y substitution is unambiguously associated with the haemochromatosis phenotype, haemochromatosis patients homozygous for the substitution (Tyr/Tyr) accounting for 81.2% of all haemochromatosis patients. A clear heterogeneity in serum ferritin and transferrin saturation values, and in iron removed by phlebotomy was observed among haemochromatosis patients that is correlated with the presence of two subgroups of individuals homozygous and non-homozygous for the mutant allele C282Y, the latter being characterized by lower phenotypic values. In this subgroup, sequencing did not reveal any other mutation in the HLA-H gene, hence the genotype remained unclear. Thus, an additional non-genetic cause, other mutations or another gene can not be excluded as explanations for the results in these patients.

Female↗
PubMed1997

TP53 and oesophageal cancer.

Mutations of the tumor suppressor gene TP53 have been detected in tumor tissues of a large variety of human malignancies and contribute to the development, progression and probably the prognosis of the disease. The pattern of somatic mutations in the TP53 gene in human tumors most often consists of a point mutation in one allele accompanied by loss or rearrangement of the second allele. Esophageal cancer is one of the most commonly mutated cancer, p53 mutations having an incidence greater than 80% in squamous cell carcinoma. The profile of distribution of these mutations in the TP53 gene is of interest to establish correlation between the exposure to carcinogens responsible for DNA mutations. The other form of esophageal cancer, Barrett's esophageal is a good model to study the role of TP53 in mammalian tumorigenesis.

Barrett Esophagus↗
PubMed1996

An exceptional genealogy for hereditary chronic pancreatitis.

Nearly one hundred families affected with hereditary chronic pancreatitis (HCP) have been reported in the literature. However, the fact that the disease involved only a few members of each family limits the informativeness of these reports and accounts for the infrequency and disappointing results of pathogenetic and genetic research. Our study concerned an exceptional HCP genealogy which would seem to provide an ideal model for the detection of a genetic anomaly linked to the expression of the disease. We studied 249 members of a family (214 still alive), covering eight generations born between 1800 and 1993. According to the customary criteria, 63 had definite and 17 probable HCP. Fifty-eight members under 18 years of age were still susceptible to developing the disease. This series confirms the mode of autosomal dominant heredity with variable penetrance. The clinical features and disease course were typical, except that symptoms tended to appear earlier. The series represents the most extensive HCP genealogy compiled and is one of the largest families studied in the field of genetic disease, regardless of etiology. Blood samples were taken from 146 subjects to facilitate pathogenetic and genetic research.

Chronic Disease↗
PubMed1995

The use of epididymal and testicular spermatozoa for intracytoplasmic sperm injection: the genetic implications for male infertility.

The results and rationale of using testicular and epididymal spermatozoa with intracytoplasmic sperm injection (ICSI) for severe cases of male infertility are reviewed. A total of 72 consecutive microsurgical epididymal sperm aspiration (MESA) cases were performed for congenital absence of the vas (CAV) and for irreparable obstructive azoospermia. ICSI was used to obtain normal embryos for transfer and fertilization in 90% of the cases. The overall fertilization rate was 46% with a normal cleavage rate of 68%. The pregnancy and delivery rates per transfer were 58 and 37% respectively. The delivery rate per cycle was 33%. In many cases, no epididymal spermatozoa were available and so testicular sperm extraction (TESE) was used for sperm retrieval. The transfer rate was lower with TESE (84 versus 96%) and the spermatozoa could not be frozen and saved for use in future cycles. However, there was little difference in pregnancy rates using epidiymal or testicular spermatozoa. The results were not affected by whether the obstruction was caused by CAV or failed vasoepididymostomy. Both fresh and frozen spermatozoa gave similar results; the only significant factor appeared to be the age of the female. Because of the consistently good results obtained using epididymal sperm with ICSI when compared with conventional IVF, and the similarly good results with testicular tissue spermatozoa, ICSI is mandatory for all future MESA patients. All CAV patients and their partners should be offered genetic screening for cystic fibrosis; hence pre-implantation embryo diagnosis should be available in any full service MESA programme. It is now clear that even with non-obstructive azoospermia, e.g. Sertoli-cell only, or maturation arrest, there are usually some small foci of spermatogenesis which allow TESE with ICSI to be carried out. This means that even in men with azoospermia due to absence of spermatogenesis or to a block in meiosis, there are usually a few spermatozoa available in the testes that are adequate for successful ICSI. Finally, it is likely that some forms of severe male factor infertility are genetically transmitted and although ICSI offspring have been shown to be completely normal, it is possible that the sons of these infertile couples will also require ICSI when they grow up and wish to have a family.

Adult↗
PubMed1994

HLA-DRB and -DBQ typing by PCR amplification using sequence-specific primers (PCR-SSP): assessment after 1 year of routine use by three laboratories.

Using sequence-specific amplifications, a practical and fast technique for DRB and DQB typing has been developed. The primers are chosen in order to amplify groups of alleles corresponding to the same serological specificity. In a second step, precise allelic determination is obtained by studying the restriction fragment length polymorphism of the PCR products. The experience of three laboratories using this technique in the context of organ or bone marrow transplantation is reported.

Alleles↗
PubMed1993

Detection of more than 94% cystic fibrosis mutations in a sample of Belgian population and identification of four novel mutations.

We have analysed 194 Belgian CF chromosomes using a variety of techniques: delta F508 was detected by polyacrylamide gel electrophoresis; dot blotting of PCR products was used to identify the mutations G542X, 1717-1 G-->A, and N1303K; molecular defects in exons 2, 3, 4, 5, 6b, 7, 11, 12, 13, 14a, 14b, 17b, 19, 20, and 21 were screened for by DGGE. We identified 17 mutations, which accounted for 94.3% of the Belgian CF chromosomes. Four novel mutations and a novel polymorphism were characterized. The detection of such a high proportion of Belgian CF mutations is important in understanding the functional role of the molecule and in improving prenatal and genetic diagnosis of CF.

Adolescent↗
PubMed1993

Asymptomatic carrier of two CFTR mutations: consequences for prenatal diagnosis?

The cystic fibrosis (CF) gene has been observed to have the highest frequency of mutations in the Caucasian population. Prenatal diagnosis can now be performed with a high degree of accuracy since the identification of most of the gene's mutations, as well as the characterization of intragenic markers. However, the observation of a distribution of clinical phenotypes increases the need to identify a mild phenotype and avoid false-negative diagnosis. By screening most of the exons of the CFTR gene, we showed that a supposed obligate carrier of CF was in fact an asymptomatic affected woman.

Base Sequence↗
PubMed1992

Intra- and extragenic marker haplotypes of CFTR mutations in cystic fibrosis families.

In order to facilitate the screening for the less common mutations in the cystic fibrosis (CF) gene viz., the CF transmembrane conductance regulator gene (CFTR), marker haplotypes were determined for German non-CF (N) and CF chromosomes by polymerase chain reaction analysis of four polymorphisms upstream of the CF gene (XV-2c, KM.19, MP6-D9, J44) and six intragenic polymorphisms (GATT, TUB9, M470V, T854T, TUB18, TUB20) that span the CFTR gene from exon 6 through exon 21. Novel informative sequence variants of CFTR were detected in front of exons 10 (1525-61 A or G), 19 (3601-65 C or A), and 21 (4006-200 A or G). The CF locus exhibits strong long-range marker-marker linkage disequilibrium with breakpoints of recombination between XV-2c and KM.19, and between exons 10 and 19 of CFTR. Marker alleles of GATT-TUB9 and TUB18-TUB20 were found to be in absolute linkage disequilibrium. Four major haplotypes encompass more than 90% of German N and CF chromosomes. Fifteen CFTR mutations detected on 421 out of 500 CF chromosomes were each identified on one of these four predominant 7-marker haplotypes. Whereas all analysed delta F508 chromosomes carried the same KM.19-D9-J44-GATT-TUB9-M470V-T854T haplotype, another frequent mutation in Germany, R553X, was identified on two different major haplotypes. Hence, a priori haplotyping cannot exclude a particular CF mutation, but in combination with population genetic data, enables mutations to be ranked by decreasing probability.

Alleles↗
PubMed1992

Improvement in HLA-DQB typing by PCR-RFLP: introduction of a constant restriction site in one of the primers for digestion control.

The PCR-RFLP method previously reported by Inoko is a powerful technique for HLA class II typing. The reliability of RFLP interpretation depends on complete digestion by restriction endonucleases using a modified primer with restriction sites as an internal digestion control. The use of restriction enzymes which recognize specific HLA DQB allelic variations makes HLA DQB genotyping possible.

Alleles↗