Prenatal diagnosis for cystic fibrosis using SSCP analysis.
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Cystic Fibrosis↗
Biomedical subjects
J Demaille
Publications and source records attributed to J Demaille.
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↗
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↗
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↗
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↗
[Mice SI/Col: a study model in the research of genes involved in situs inversus].
The SI/Col mouse is carrier of the i.v. mutation which expresses itself in an autosomal recessive mode. Fifty per cent of mice born of homozygotic i.v./i.v. parents are normal and 50% present an abnormality of lateralisation of the thoracic and abdominal organs with cardiac malformations involving the venous, atrial, ventricular and arterial segments. Identifying the i.v. mutation may improve our understanding of the genesis of the heterotaxic syndrome in man. With the help of return crossing with wild mice, the authors studied segregation of 10 makers of the murine, chromosome 12 of the situs inversus mice. The genetic map constructed from this data places the i.v. mutation near the telomeric extremity of the murine chromosome 12. Given the inter-species conservation between this region and the telomeric region of the human chromosome 14, it is a candidate region for the search of a homologous human gene in syndromes of heterotaxis.
Animals↗
A new intragenic polymorphism detected by the single-strand conformation polymorphism (SSCP) assay in the dystrophin gene.
We have employed the single strand conformation polymorphism (SSCP) technique to examine a group of patients with Duchenne or Becker muscular dystrophy who do not contain deletions detectable by multiplex PCR or Southern/cDNA, in an attempt to identify uncommon mutations within the dystrophin gene. In SSCP analysis, a mutated sequence can be detected as a change of mobility in a nondenaturing polyacrylamide gel. During the course of this investigation, we detected and characterized a new polymorphism at the 3' end of intron 16. The G-to-T base change creates a TaqI restriction site which allows for rapid typing of the polymorphism by restriction digestion and electrophoresis of PCR amplified products. Its localization inside the 5' region of the dystrophin gene and its high heterozygosity makes it a useful and easy tool for rapid carrier and prenatal diagnosis.
Base Sequence↗
Screening for cystic fibrosis mutations in southern France: identification of a frameshift mutation and two missense variations.
In the search for mutations in the cystic fibrosis gene in patients from the Mediterranean area, we have analysed exons 4, 9, 10, 19, and 21 by the single-strand conformation polymorphism (SSCP) technique in 50 patients with at least one non-delta F508 chromosome. Ten samples demonstrated a shifted band, four in exon 19 and six in exon 21. Sequencing of the PCR fragments has led to the identification of three new sequence alterations, two in exon 19 (3737 delA and I1234V), and one in exon 21 (N1303H). We also analysed the frequency of two known intronic polymorphisms in front of exon 19 (C to A change at nucleotide 3601-65) and exon 21 (G to A change at position 4006-200).
Base Sequence↗
Potential co-existence of haemophilia A and B carrier status in two sisters.
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Chorionic Villi Sampling↗
Analysis of 30 known cystic fibrosis mutations: 10 mutations account for 27% of non-delta F508 chromosomes in southern France.
We have analyzed 131 unrelated families from Southern France for 29 known cystic fibrosis (CF) mutations identified in 8 exons of the cystic fibrosis transmembrane regulator gene. All these mutations were detected by amplification of DNA by the polymerase chain reaction (PCR) followed by restriction enzyme digestion or hybridization with allele specific oligoprobes. The most frequent mutations after the delta F508 deletion (frequency: 63%) were G542X (5.3%), delta I507 (1.1%), and N1303K (0.76%). Seven other mutations (621 + 1G --> T, Y122X, R347P, R334W, S549N, G551D, R1162X) were each identified in only one CF chromosome. Apart from G542X, most of the other mutations identified in this study were found to be associated with 7-(GATT)-repeats allele of IVS6A. In Southern France, only 73% of CF chromosomes could be identified by the analysis of 30 mutations.
Chromosomes, Human↗
A detailed linkage map of subtelomeric murine chromosome 12 region including the situs inversus mutation locus IV.
A mouse model is an invaluable tool to tackle genesis of human congenital diseases that have so far eluded human studies. Homozygote for the i.v. mutation, the murine Si/Col strain presents a left-right lateralization defect of thoracic and abdominal organs and heart defects very similar to human ones. This i.v. mutation has been mapped to the region between the Aat and Igh-C loci, suggesting the presence of an equivalent human gene in the human syntenic 14q3 region. A precise linkage map of the region is, therefore, of great interest since it will contribute to the genetic approach of the i.v. gene. Analysis of 242 back-cross progeny from Mus musculus (MAI) or spretus strains of mice and SI/Col mice has allowed mapping of the i.v. gene to a linkage group of eight markers. It includes four genes: Aat (alpha 1-antitrypsin), Ckb (creatine kinase, brain form), Crip (cysteine-rich intestinal protein), and Igh-C (immunoglobulin heavy chain constant region complex); three murine microsatellites: D12Mit6, D12Mit7, and D12Mit8; and one new marker, D12Mtp1, defined by a minisatellite human probe, pYNZ2. After analysis of the data by the LINKAGE program, the following multilocus map has been constructed: centromere-D12Mit6-6.9 cM-D12Mit7-1.7 cM-D12Mtp1-2.6 cM-Aat-5.0 cM-(Ckb, Igh-C)-0.4 cM-D12Mit8-0.4 cM-Crip-11.2 cM-i.v.-telomere. This map differs from the previous map in placing i.v. locus telomeric to Igh-C. D12Mit6 and D12Mit7 are now precisely mapped centromeric to the locus Aat. In addition, a new locus D12Mtp1 is located between Aat and D12Mit7.
Animals↗
Becker muscular dystrophy: demonstration of the carrier status of a female by immunoblotting and immunostaining.
Becker muscular dystrophy (BMD) often results from in-frame mutations of the dystrophin gene, leading to the production of an altered-sized protein. We examined the expression of dystrophin in a BMD patient and in his asymptomatic mother by Western blot and immunofluorescence. The combination of these techniques allowed us to demonstrate the presence of two different dystrophins, normal-sized or reduced-sized in the muscular fibers of the asymptomatic carrier. This result emphasizes the value of dystrophin analysis for carrier detection and genetic counselling of families with Becker muscular dystrophy.
Adolescent↗
Molecular deletion patterns in families from southern France with Duchenne/Becker muscular dystrophies.
We studied 38 unrelated patients from southern France with Duchenne (DMD) or Becker (BMD) muscular dystrophy for intragenic deletions of the DMD/BMD gene. We used both multiplex amplification of selected exons and cDNA probes. Of the 26 (68%) unrelated individuals found to have deletions, 24 (92%) were detected by multiplex polymerase chain reaction. All these deletions have been delineated with regard to the exon-containing HindIII fragments revealed by cDNA probes, and in two cases, junction fragments of altered size were seen. The correlation between phenotype and type of deletion agreed with the reading frame theory, except for two BMD and two DMD cases.
Adolescent↗
Evidence for aggregation of endothelin 1 in water.
In this report it is shown by CD spectroscopy that endothelin 1, when dissolved in water, is able to present intermolecular interactions leading to formation of aggregates. Surface tension and conductivity measurements suggest that the aggregation occurs through formation of micelles with a CMC of about 2.2 x 10(-5) M.
Chromatography, High Pressure Liquid↗
Germinal mosaicism from grand-paternal origin in a family with Duchenne muscular dystrophy.
We have identified a Duchenne muscular dystrophy (DMD) pedigree with an unexpected pattern of inheritance. Using marker restriction fragment length polymorphisms detected by probes that lie within and outside the DMD gene, we could demonstrate that the maternal grandfather has transmitted two distinct types of X chromosomes to his offspring. This original observation may be explained by postulating that the DMD mutation must have occurred during mitosis in early germline proliferation, leading to a germline mosaicism within this male ancestor.
DNA Probes↗
Cystic fibrosis typing with DNA probes and screening for delta F508 deletion in families from southern France.
A sample of 235 individuals from 49 French cystic fibrosis (CF) families with at least one living affected child was typed with probes for restriction fragment length polymorphisms (RFLPs) known to be linked to the CF gene, and was screened for the delta F508 mutation. Using a combination of six probes, 44 out of the 49 families were sufficiently informative to enable prenatal diagnosis or carrier determination. As in many other populations, linkage disequilibrium was found between the CF locus and the haplotype B (XV2c: allele 1; KM19: allele 2), which accounts for about 78% of CF chromosomes in our families. The delta F508 deletion was present in 64.3% of CF chromosomes.
Chromosome Deletion↗
Reconstituted skin in culture: a simple method with optimal differentiation.
Human skin is a unique organ, which can be reconstituted in vitro and represents an interesting system for studying cell proliferation and differentiation. A simple technique for producing reconstituted skin with optimal epidermal differentiation is described and characterized. A 4-mm punch biopsy of normal human skin is deposited on the epidermal side of mortified de-epidermized human dermis maintained at the air-liquid interface with a metallic support. The culture medium contains insulin, epidermal growth factor (EGF), cholera toxin, hydrocortisone, penicillin/streptomycin and fungizone. A well-differentiated epidermis develops within 15 days. Morphological and ultrastructural studies show a neoepidermis resembling normal skin. Differentiation markers such as involucrin, filaggrin, and various cytokeratins detected with pancytokeratin antibody are present and confirm this resemblance. The keratin profile is comparable to that observed in other skin culture models. A basement-membrane-like structure is reconstituted with hemidesmosomes and anchoring-filament formation. Bullous pemphigoid (BP) antigen is observed at the dermo-epidermal junction after 21 days of culture. Moreover, both dermal substrates and punch biopsies can be kept frozen for long-term storage, with little or no loss of epidermal growth kinetics and morphology. This skin culture technique is rapid, simple, economical and reproducible. Characterization has here shown high-quality epidermal differentiation. Scientists interested in epidermal in vitro studies should take interest in all these advantages.
Antibodies, Monoclonal↗
Identification of carriers by screening for delta F508 deletion in a multi-generation cystic fibrosis family.
Samples from 30 members of a french cystic fibrosis (CF) family had to be typed with probes for restriction fragment length polymorphisms (RFLPs) known to be linked to the CF gene, to fulfill the expectations of twenty-two low-risk relatives who were asking for carrier testing. Classical linkage-disequilibrium data between KM-19 and XV-2c polymorphisms and the CF locus were not informative enough for some individuals, and other RFLPs had to be analyzed to determine which chromosomes carried the deficient gene in the family. We report the retrospective screening for delta F508 mutation in this extended family to illustrate the drastic improvements that the direct detection of the major mutation responsible for CF has on genetic counselling of relatives of patients with cystic fibrosis.
Blood Proteins↗