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M Claustres

Publications and source records attributed to M Claustres.

At least 91 records · Page 5Linked to original sources
PubMed1994

Analysis of the whole CFTR coding regions and splice junctions in azoospermic men with congenital bilateral aplasia of epididymis or vas deferens.

Several recent studies have demonstrated the presence of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in healthy males with infertility caused by congenital absence of the vas deferens (CBAVD), previously recognized as an idiopathic genetic condition distinct from CF. In order to document further the genetic commonality of these two disorders, we undertook a double screening of the entire coding and flanking sequences of the CFTR gene, by using single-strand conformational polymorphism analysis and denaturing gradient gel electrophoresis in 12 unrelated infertile men with abnormalities of the vas deferens and/or epididymis. This strategy allowed us to identify 11 DNA sequence alterations considered as CF-causing mutations and several variations. Despite this double analysis, only two patients out of eight with CBAVD could be demonstrated as compound heterozygotes for CF mutations.

Adult↗
PubMed1994

Factor IX gene mutations causing haemophilia B: comparison of SSC screening versus systematic DNA sequencing and diagnostic applications.

The search for mutations of the factor IX gene responsible for haemophilia B should nowadays be used routinely for the molecular diagnosis of this inherited disorder, i.e. carrier detection and prenatal diagnosis. A number of methodologies have been proposed, most of them being delicate or expensive. We have used a simple strategy based on a preliminary screening of eight factor IX gene fragments by single-strand conformation analysis (SSCA), followed by direct sequencing of fragments displaying an abnormal migration pattern. Carrier testing is then performed by use of an enzyme restriction site altered by the mutation or by the SSCA itself. By using this strategy we were able readily to identify the factor IX molecular defect of nine unrelated haemophilia B patients from southern France. We validated the efficiency and reliability of the SSC-based detection of mutations by sequencing all the polymerase chain reaction (PCR) fragments studied in the haemophilic patients. No other sequence alteration could be found except the one detected by SSC analysis. We conclude that this method can be advantageously used for diagnosis purposes in a routine laboratory involved in haemophilia B diagnosis and report nine previously undescribed haemophilia B families with their factor IX mutation.

DNA Mutational Analysis↗
PubMed1994

394delTT: a Nordic cystic fibrosis mutation.

In a systematic screening for mutations in the gene encoding the cystic fibrosis transmembrane regulator among Danish cystic fibrosis (CF) patients, we identified a mutation in exon 3 (394delTT); this mutation was found to be relatively common in Denmark. We therefore screened for 394delTT in Sweden and Norway, where it turned out to be the second most frequent mutation, accounting for 4% of all CF mutations. It also occurs with a high frequency in Finland, but has not been found in larger surveys of mutations in the CFTR gene. Thus, 394delTT seems to be a specific Nordic CF mutation.

Base Sequence↗
PubMed1994

Direct carrier testing of haemophilia B by SSCP.

Haemophilia B is due to multiple molecular defects in the factor IX gene. Most of them are single base substitutions, and can now be identified by direct sequencing of the coding sequence of the factor IX gene, preceded or not by a screening strategy. In some instances the mutation alters an enzyme recognition site and this allows rapid and accurate carrier testing and prenatal diagnosis in the affected pedigree. This was not the case for the previously described nt 31119 (G-->A) mutation that we found in an extended haemophilia B pedigree, during the search for mutations in the factor IX gene in patients from Southern France. We first detected this mutation by single stranded conformation polymorphism (SSCP) and then identified it by DNA sequencing. Carriership could be easily determined in the females of the pedigree by analysis of the SSCP patterns. Our results indicate that the SSCP analysis of amplified genomic DNA fragments can be successfully used as a diagnosis approach for direct carrier testing and prenatal diagnosis.

Base Sequence↗
PubMed1993

Base substitutions in the human dystrophin gene: detection by using the single-strand conformation polymorphism (SSCP) technique.

We have established the experimental conditions to screen twenty regions of the dystrophin gene using the method of single-strand conformational polymorphism (SSCP) analysis. The aim of this study was to identify point mutations in patients with Duchenne or Becker muscular dystrophy (DMD or BMD) who have no gross DNA rearrangements detectable by Southern blot analysis or multiplex exon amplification. The investigation of thirteen patients using this procedure resulted in the detection of seven sequence polymorphisms (four identified in this study) that will be useful allelic markers in familial DNA analysis. Three rare sequence variants could be found (two of them being novel variants) but we were unable to demonstrate mutations that could be clearly sufficient to be responsible for the phenotype. This analysis confirmed the efficiency of the SSCP technique for the detection of nucleotide substitutions. Application of this approach to mutation or polymorphism detection to other exons of the gene will improve carrier and prenatal diagnosis.

Base Composition↗
PubMed1993

Rapid detection of single nucleotide deletions: application to the beta 6 (-A) mutation of the beta-globin gene and to cystic fibrosis.

The formation of heteroduplexes from the amplified products of homologous alleles has been shown to be useful in the identification of heterozygotes carrying deletion or insertion mutations. Here, we describe an improved procedure that allows the detection of single base pair (bp) deletions on nondenaturing polyacrylamide gels. Carriers for a common Mediterranean beta-thalassemic mutation, beta6 (-A), could be easily detected by use of this method, as could carriers of a 1-bp deletion in the cystic fibrosis gene.

Base Sequence↗
PubMed1993

Comparison of the protein and DNA approaches for the characterization of a beta-globin chain variant, hemoglobin Cocody [beta 21 (B3) Asp--->Asn], in a Caucasian patient.

Over the past few years, the methodologies used for the identification of hemoglobin A variants have been greatly improved. Both the protein- and DNA-based strategies have their own advantages and limitations. In this report we illustrate the use of both assays for the characterization of a hemoglobin Cocody variant in a women of Spanish descent. After evaluating the mobility value matrix of the abnormal hemoglobin, the amino acid transition was determined by HPLC and micro-sequencing of the protein. The beta 21 Asp was shown to be substituted by an Asn. At the DNA level, the only nucleotide replacement responsible for this amino acid substitution is GAT--->AAT at codon 21. The analysis of the beta-globin gene by denaturing gradient gel electrophoresis (DGGE) method showed that the mutation was situated in a fragment including exon 1. The hemoglobin variant was then identified to be hemoglobin Cocody by DNA sequencing of this fragment.

Adult↗
PubMed1993

Analysis of the 27 exons and flanking regions of the cystic fibrosis gene: 40 different mutations account for 91.2% of the mutant alleles in southern France.

In order to characterize the non-delta F508 mutations that account for 36% of cystic fibrosis (CF) chromosomes in Southern France in a sample of 137 patients, we have systematically screened the entire coding region and adjacent sequences of the cystic fibrosis transmembrane conductance regulator (CFTR) gene by the single strand conformation polymorphism (SSCP) technique followed by direct sequencing of the mutant DNAs. We identified 13 novel mutations (9 reported in this paper) and 4 novel rare nucleotide sequence variations. Forty different mutations including delta F508, located in 15 exons, account for only 91.2% of mutants in a population originating from Southern France, in contrast with a recent report on the Celtic population of Brittany demonstrating that 90% of mutations can be detected with only three mutations. We present a very large spectrum of different CF mutations identified in a small geographical area.

Alleles↗
PubMed1993

DNA analysis of haemophilia A families from southern France. Experience of a hospital laboratory.

A sample of 101 individuals from 19 unrelated families from Southern France affected with haemophilia A was studied in our laboratory from 1990 to 1992. The aim of the analysis was to define the carrier status of women related to a haemophiliac, or to find an informative DNA marker for further prenatal diagnosis in obligate carriers. Three intragenic (BclT/intron 18, XbaI/intron 22, AlwNI/intron x7) and two extragenic polymorphisms (TaqI/St14, BglII/DX13) were used for this study. The tested population exhibited some original characteristics, including a lower rate of heterozygosity for the FVIII BclI polymorphism and a number of specificities for the St14 RFLP. We also compared the different methodologies available for each RFLP in a routine diagnostic service, and determined a strategy for linkage analysis in our population.

Adult↗