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J Demaille

Publications and source records attributed to J Demaille.

At least 73 records · Page 4Linked to original sources
PubMed1995

An isolated cardiac conduction disease maps to chromosome 19q.

Isolated cardiac conduction disease is an autosomal dominant defect that includes various combinations of bundle branch or fascicular blocks. These defects can cause sudden death due to a complete heart block. We used a genome-wide screening approach with polymorphic (CA)n repeat markers to determine the chromosomal position of the gene defect implicated in this disorder. The analyses were carried out on a large Lebanese kindred, which included individuals with either a complete or incomplete right bundle branch block (RBBB) with a vertical-axis deviation (< or = -30 or > or = +100). Linkage to the disease locus was detected with the polymorphic marker D19S604 on the q arm of chromosome 19 (19q13.3) with a multipoint lod score of 7.18. Additionally, we were able to exclude the flanking loci D19S606 and D19S571, which are 13 cM apart because of recombination events in three affected individuals. The histidine-rich calcium-binding protein gene is found in this region and is an attractive candidate gene on the basis of its physiological properties and a tight linkage. There is no expansion in two exon 1 regions known for a variable number of triplet repeats.

Base Sequence↗
PubMed1995

Direct carrier detection for severe haemophilia A: application to families with no available affected male.

Haemophiliae A is a common hereditary disorder of blood coagulation resulting from deficiency of factor VIII. Mutation analysis is the factor VIII gene has been hampered by the large size of the gene and the heterogeneity of molecular defects. In severe haemophiliae A, the most efficient methods of screening for point mutations can detect the lesions in 50 percent of cases only; this is explained by the recent finding (5) of an intragenic inversion that disrupts the factor VIII gene. Since this anomaly could not be characterized by these methods, Lakich et al. have also described a Southern blotting assay that allows a direct determination of the mutation. The use of this assay should greatly increase the feasibility and accuracy with which carrier detection and prenatal diagnosis can be made, as illustrated by the analysis of families with no available affected male that we present here.

Adult↗
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

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↗
PubMed1994

[Expression and localization of dystrophin during human skeletal, cardiac and smooth muscle development].

Dystrophin, the Duchenne muscular Dystrophy gene product, is a large cytoskeletal protein associated with a complex of membrane proteins, the Dystrophin Glycoprotein Complex (DGC). Dystrophin is localized to the sarcolemmal membrane of all normal muscle types, but is absent from muscles of DMD patients. Using monoclonal antibodies raised against distinct regions of the dystrophin, we studied its expression and subcellular localization during human skeletal, cardiac and smooth muscle development. We have shown that the expression and the association of dystrophin with the plasma membrane take place earlier in cardiac and smooth muscles (8 weeks of gestation) than in skeletal muscles. In skeletal muscles, dystrophin is first observed in the cytoplasm, and is progressively localized to the plasma membrane from 10 weeks onwards. We obtained differences in staining when using antibodies against either the central part of the protein or the carboxy-terminal domain, and we suggested that isoforms of dystrophin, probably differing in their carboxy-terminal end and their capacity to associate with the plasma membrane were differentially expressed during development and in different tissue-types (7). These findings are discussed in the context of the pathology of Duchenne Muscular Dystrophy.

Dystrophin↗
PubMed1994

Deciphering the molecular genetics of congenital heart disease.

Congenital heart diseases are starting to benefit from the major advances provided by the advent of molecular biology methods. It is now possible to identify genes which are responsible for congenital heart diseases. The gene responsible for supravalvular aortic stenosis--an autosomal dominant trait--was cloned last year. It is the elastin gene. DiGeorge and Shprintzen syndromes, conotruncal anomaly face and some cardiac malformations have a common cause: a deletion of the 22q11 region resulting in a monosomy. Although the region of deletion is large, it is possible that monosomy of only one gene results in these conditions. Studies are underway to evaluate the impact of this new genetic factor on the incidence of congenital heart malformations. Studies on familial bundle branch block, and lateralization defect with midline anomalies are soon going to show a chromosomal region with the gene defect. Discovering the genes and their protein products which are implied in the cardiac morphogenesis will definitively change our understanding of these cardiac malformations.

Abnormalities, Multiple↗
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↗