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Biomedical subjects

C Boileau

Publications and source records attributed to C Boileau.

At least 19 recordsLinked to original sources
PubMed2003

In frame fibrillin-1 gene deletion in autosomal dominant Weill-Marchesani syndrome.

Weill-Marchesani syndrome (WMS) is a connective tissue disorder characterised by short stature, brachydactyly, joint stiffness, and characteristic eye anomalies including microspherophakia, ectopia of the lenses, severe myopia, and glaucoma. Both autosomal recessive (AR) and autosomal dominant (AD) modes of inheritance have been described and a gene for AR WMS has recently been mapped to chromosome 19p13.3-p13.2. Here, we report on the exclusion of chromosome 19p13.3-p13.2 in a large AD WMS family and show that, despite clinical homogeneity, AD and AR WMS are genetically heterogeneous entities. Because two AD WMS families were consistent with linkage to chromosome 15q21.1, the fibrillin-1 gene was sequenced and a 24 nt in frame deletion within a latent transforming growth factor-beta1 binding protein (LTBP) motif of the fibrillin-1 gene was found in a AD WMS family (exon 41, 5074_5097del). This in frame deletion cosegregated with the disease and was not found in 186 controls. This study strongly suggests that AD WMS and Marfan syndrome are allelic conditions at the fibrillin-1 locus and adds to the remarkable clinical heterogeneity of type I fibrillinopathies.

Abnormalities, Multiple↗
PubMed2001

No evidence of somatic FGFR3 mutation in various types of carcinoma.

Germline specific point mutations in the gene encoding fibroblast growth factor receptor 3 (FGFR3) are associated with autosomal dominant human skeletal dysplasia and craniosynostosis syndromes. Mutations identical to the germinal activating mutations found in severe skeletal dysplasias have been identified in certain types of cancer: at low frequency in multiple myeloma and cervix carcinoma and at high frequency in bladder carcinoma. We analysed, by SSCP and sequencing, the prevalence of FGFR3 mutations in 116 primary tumours of various types (upper aerodigestive tract, oesophagus, stomach, lung and skin). The regions analysed encompassed all FGFR3 point mutations previously described in severe skeletal dysplasia and cancers. No mutations were detected in the tumour types examined, suggesting that FGFR3 mutations are restricted to a few tumour types, the evidence to date suggesting that they are very specific to bladder carcinomas.

Bone Diseases, Developmental↗
PubMed2001

[Factors associated with refusal of organ donation in France from 1996 to 1999].

OBJECTIVE: The demand for organ transplantation exceeds organ donation in France and refusal to organ donation remains close to 30%. This study analysed risk factors associated with refusal of organ donation. STUDY DESIGN: Retrospective study. PATIENTS: All potential organ donors registered by the French transplantation agency between 1996 and 1999 were included, excepted those with a contraindication to organ procurement or a logistic problem: 5,911 donors were included. METHODS: Data analysed were those collected routinely on the French database. A logistic model was used to identify statistically significant factors and a stepwise procedure was performed to identify independent factors linked with refusal. RESULTS: In univariate analysis, age > 60 years and age < 13 years, stroke, lack of suicide, localisation in an university hospital and in others regions than the Centre-East of France were associated with a higher refusal rate. Year of harvesting, low level of organ procurement activity were not associated with refusal. In multivariate analysis, factors independently associated with refusal were age > 60 years [Odds-Ratio (OR) = 1.2)] or age < 13 years (OR = 1.5), stroke (OR = 1.2), meningitis and cranial tumour (OR = 1.4), suicide (OR = 0.5) and others French regions than Centre-East. CONCLUSION: The risk factors described should be taking into account when family's members are approached for donation. They represent the interactions between the history of the donors, harvesting organisation, and sociocultural factors.

Adolescent↗
PubMed2000

Regulation of extrathymic T cell development and turnover by oncostatin M.

Chronic exposure to oncostatin M (OM) has been shown to stimulate extrathymic T cell development. The present work shows that in OM transgenic mice, 1) massive extrathymic T cell development takes place exclusively the lymph nodes (LNs) and not in the bone marrow, liver, intestines, or spleen; and 2) LNs are the sole site where the size of the mature CD4+ and CD8+ T cell pool is increased (6- to 7-fold). Moreover, when injected into OM transgenic mice, both transgenic and nontransgenic CD4+ and CD8+ T cells preferentially migrated to the LNs rather than the spleen. Studies of athymic recipients of fetal liver grafts showed that lymphopoietic pathway modulated by OM was truly thymus independent, and that nontransgenic progenitors could generate extrathymic CD4+CD8+ cells as well as mature T cells under the paracrine influence of OM. The progeny of the thymic-independent differentiation pathway regulated by OM was polyclonal in terms of Vbeta usage, exhibited a phenotype associated with previous TCR ligation, and displayed a rapid turnover rate (5-bromo-2'-deoxyuridine pulse-chase assays). This work suggests that chronic exposure to OM 1) discloses a unique ability of LNs to sustain extrathymic T cell development, and 2) increases the number and/or function of LN niches able to support seeding of recirculating mature T cells. Regulation of the lymphopoietic pathway discovered in OM transgenic mice could be of therapeutic interest for individuals with thymic hypoplasia or deficient peripheral T cell niches.

Animals↗
PubMed2000

UMD (Universal mutation database): a generic software to build and analyze locus-specific databases.

The human genome is thought to contain about 80,000 genes and presently only 3,000 are known to be implicated in genetic diseases. In the near future, the entire sequence of the human genome will be available and the development of new methods for point mutation detection will lead to a huge increase in the identification of genes and their mutations associated with genetic diseases as well as cancers, which is growing in frequency in industrial states. The collection of these mutations will be critical for researchers and clinicians to establish genotype/phenotype correlations. Other fields such as molecular epidemiology will also be developed using these new data. Consequently, the future lies not in simple repositories of locus-specific mutations but in dynamic databases linked to various computerized tools for their analysis and that can be directly queried on-line. To meet this goal, we devised a generic software called UMD (Universal Mutation Database). It was developed as a generic software to create locus-specific databases (LSDBs) with the 4(th) Dimension(R) package from ACI. This software includes an optimized structure to assist and secure data entry and to allow the input of various clinical data. Thanks to the flexible structure of the UMD software, it has been successfully adapted to nine genes either involved in cancer (APC, P53, RB1, MEN1, SUR1, VHL, and WT1) or in genetic diseases (FBN1 and LDLR). Four new LSDBs are under construction (VLCAD, MCAD, KIR6, and COL4A5). Finally, the data can be transferred to core databases.

Chromosome Mapping↗
PubMed2000

Mutation analysis in a small cohort of New Zealand patients originating from the United Kingdom demonstrates genetic heterogeneity in familial hypercholesterolemia.

Familial hypercholesterolemia (FH) and familial defective apolipoprotein B-100 (FDB) are relatively common lipid disorders caused by mutations in the low-density lipoprotein receptor (LDLR) and apolipoprotein B (apo B) genes, respectively. Molecular analysis at these loci was performed in eight New Zealand subjects with clinical features of heterozygous FH. Utilization of an in vitro lymphocyte receptor assay demonstrated normal receptor function in four patients, three of whom screened positive for the founder-type apo B mutation, R3500Q, causing FDB. Four patients with reduced LDLR function, consistent with heterozygous FH, revealed three previously documented mutations in exons 3 (W66X), 6 (C292Y) and 7 (G322S) of the LDLR gene and, a novel 2-bp deletion (TC or CT) after nucleotide 1204 (or 1205) in exon 9. The remaining patient was found to be FH/FDB negative after extensive mutation screening using both denaturing gradient gel electrophoresis and heteroduplex-single strand conformation polymorphism analysis. Haplotype analysis at the LDLR and apo B loci finally excluded the likelihood that mutations in these two genes underlie the FH phenotype in the molecularly uncharacterized New Zealand family originating from the United Kingdom. This family represents a valuable source of material for future genetic dissection of autosomal dominant hypercholesterolemia (ADH), shown to be a heterogeneous disease through molecular analysis.

Adult↗
PubMed2000

Autosomal dominant type IIa hypercholesterolemia: evaluation of the respective contributions of LDLR and APOB gene defects as well as a third major group of defects.

Autosomal dominant type IIa hypercholesterolaemia (ADH) is characterised by an elevation of total plasma cholesterol associated with increased LDL particles. Numerous different molecular defects have been identified in the LDL receptor (LDLR) and few specific mutations in the apolipoprotein B (APOB) gene resulting in familial hypercholesterolaemia and familial defective apoB-100 respectively. To estimate the respective contribution of LDLR, APOB and other gene defects in this disease, we studied 33 well characterised French families diagnosed over at least three generations with ADH through the candidate gene approach. An estimation of the proportions performed with the HOMOG3R program showed that an LDLR gene defect was involved in approximately 50% of the families (P = 0.001). On the other hand, the estimated contribution of an APOB gene defect was only 15%. This low estimation of ADH due to an APOB gene defect is further strengthened by the existence of only two probands carrying the APOB (R3500Q) mutation in the sample. More importantly and surprisingly, 35% of the families in the sample were estimated to be linked to neither LDLR nor APOB genes. These data were confirmed by the exclusion of both genes through direct haplotyping in three families. Our results demonstrate that the relative contributions of LDLR and APOB gene defects to the disease are very different. Furthermore, our results also show that genetic heterogeneity is, generally, underestimated in ADH, and that at least three major groups of defects are involved. At this point, the contribution of the recently mapped FH3 gene to ADH cannot be assessed nor its importance in the group of 'non LDLR/non APOB' families.

Apolipoproteins B↗
PubMed2000

R3531C mutation in the apolipoprotein B gene is not sufficient to cause hypercholesterolemia.

Familial hypercholesterolemia and familial ligand-defective apolipoprotein B-100 (FDB) are dominantly inherited disorders leading to impaired low-density lipoprotein receptor (LDLR) and apolipoprotein B-100 (APOB) interaction, plasma LDL elevation, and hypercholesterolemia. We previously identified the first French FDB-R3531C proband, a woman with very high total cholesterol, in a group of type IIa hypercholesterolemic families. We report here the investigation of her family at large that revealed the total absence of cosegregation with hypercholesterolemia. Six of the 10 subjects heterozygous for the R3531C mutation had plasma cholesterol lower than the 97.5th percentile for their age and gender, and mean cholesterol levels were not significantly different between affected and unaffected persons. Furthermore, 2 family members with similar high LDL-cholesterol levels were not carriers of the R3531C substitution, suggesting the implication of another mutation. Segregation analysis of the LDLR gene revealed statistically significant genetic linkage with hypercholesterolemia, and analysis of the proband LDLR gene led to the identification of the 664 proline to leucine defective mutation and its detection in all 6 hypercholesterolemic-related members of this family. Therefore, our results show that the family presents with familial hypercholesterolemia and give evidence that the R3531C substitution in the APOB gene is not an allelic variant leading to FDB. Furthermore, thorough analysis of our data suggests that the APOB-R3531C mutation enhances the hypercholesterolemic effect of the LDLR-P664L defect, suggesting that it is a susceptibility mutation.

Adolescent↗
PubMed2000

[Fibrillin network in normal bone tissue].

The molecular basis for Marfan's syndrome is known to reside in mutations in FBN1, the gene for fibrillin 1. The skeletal manifestations of Marfan syndrome include morphologic abnormalities and osteopenia. Presence and distribution of fibrillin 1 in adult bone (healthy or with Marfan syndrome) has not been studied extensively. We evaluated distribution of fibrillin and type III collagen in bone and cartilage of children and adults without bone disease, using monoclonal antibodies. Fibrillin is mostly present in attachment sites for tendons. In cartilage and bone tissue, fibrillin is identified at the junction between cartilage and bone in children, and in the areas with intense osteoblastic activity. These data suggest participation of fibrillin in bone formation and growth during youth and in bone mineralisation in adult.

Adolescent↗
PubMed2000

[Pigs, do they have their heart in their hand? Anthropological reflections on xenografts].

The therapeutic perspectives initiated by xenotransplantations are of interest since they allow a great deal of hope for all patients whose transplant delays decrease in proportion to their prognosis for survival. However, this type of therapy, while resolving the qualitative problem of transplants, could possibly lead to other dilemmas, especially the sociocultural aspects. Besides the potential risk of transmission of a pathogenic agent to the human species, xenotransplants, while creating a symbolic and actual proximity between man and animal, could abolish the ritualized and ancient distance established between the protagonists. It could be pigs or any other type of animal; the central question is one of the relationship between human and animal species. Animal husbandry and slaughtering for food are submitted to very precise cultural codes. But it would be very hasty to think that the use of an animal for therapeutic transplants would be free of all cultural connotations.

Animal Husbandry↗
PubMed2000

Marfan syndrome and fibrillin disorders.

Marfan syndrome is the second most common inherited connective tissue disorder after osteogenesis imperfecta. Musculoskeletal abnormalities are at the forefront of the clinical picture and count among the major diagnostic criteria for Marfan syndrome, together with cardiovascular and ocular system involvement. Early diagnosis is of the utmost importance since preventive measures significantly increase life expectancy and prevent the occurrence of impairments and disabilities. Marfan syndrome is due to mutations within the fibrillin-1 gene, which is the main protein of the microfibril network. Microfibrils play a crucial role in the trophicity and function of elastic tissue. Multidisciplinary management of the patients and their families is vital.

Extracellular Matrix Proteins↗
PubMed1999

Bone mineral density in sixty adult patients with Marfan syndrome.

Sixty adult patients (40 women, 20 men) with Marfan syndrome (MFS) according to the Berlin criteria had a full clinical examination and bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry of the hip and nondominant forearm. BMD was expressed as a Z-score and compared with the reference population of the Hologic database. In MFS men, BMD (g/cm(2)) was compared with the BMD of 45 normal tall Caucasian adults. Osteocalcin was measured by radioimmunoassay. In patients with MFS, BMD was compared between patients with and without previous fractures and according to the phenotypic severity of MFS. The mean age of the patients was 32.9 +/- 9.3 years (women 32.5 +/- 9.7, men 33.4 +/- 8.6), mean height was 180.3 +/- 10.3 cm (women 176.3 +/- 9.2, men 188.1 +/- 7.5) and mean body mass index 20.9 +/- 3.6 kg/m(2) (women 20.8 +/- 3.4, men 20.95 +/- 3.97). Hyperlaxity score (Beighton criteria) was 6.9 +/- 1. 1. Six patients (10%) had a previous fracture. Thirty per cent of patients had had at least one previous operation for scoliosis, aortic dilatation or eye problems. BMD values in the 60 patients were as follows: Z-score of the hip, -1.26 +/- 0.93, p<10(-9) (neck, -0.93 +/- 1.09, p<10(-9); trochanter, -1.31 +/- 0.85, p<10(-9); intertrochanter, -1.39 +/- 0.99, p<10(-9); Ward's triangle, -0.93 +/- 1.88, p<10(-9)); Z-score of the radius: -1.6 +/- 1.06, p<10(-9) (1/3 proximal, -1.29 +/- 1.03; mid-radius, -1.94 +/- 1.04; ultradistal, -0.68 +/- 1.1, p<10(-9)). The decrease in BMD was similar in men and women at both the hip and the radius. BMD in MFS patients was significantly decreased at cortical compared with trabecular sites (radius 1/3 proximal vs ultradistal, p<0.0001; total femur vs Ward's triangle, p<0.0005). No difference in BMD was found between MFS patients with or without previous fractures and those with severe or less severe phenotypic expression of MFS. An influence of height and weight in MFS on BMD is suspected. Osteocalcin was not increased in our group of MFS patients. Thus both men and women with MFS have a significant deficit of BMD at the hip and radius. The decrease in BMD is present equally in both sexes and is more pronounced at predominantly cortical sites. In our group of patients we found no increase in fractures and no relation between decreased BMD and phenotypic expression of the syndrome.

Absorptiometry, Photon↗
PubMed1999

A third major locus for autosomal dominant hypercholesterolemia maps to 1p34.1-p32.

Autosomal dominant hypercholesterolemia (ADH), one of the most frequent hereditary disorders, is characterized by an isolated elevation of LDL particles that leads to premature mortality from cardiovascular complications. It is generally assumed that mutations in the LDLR and APOB genes account for ADH. We identified one large French pedigree (HC2) and 12 additional white families with ADH in which we excluded linkage to the LDLR and APOB, implicating a new locus we named "FH3." A LOD score of 3.13 at a recombination fraction of 0 was obtained at markers D1S2892 and D1S2722. We localized the FH3 locus to a 9-cM interval at 1p34.1-p32. We tested four regional markers in another set of 12 ADH families. Positive LOD scores were obtained in three pedigrees, whereas linkage was excluded in the others. Heterogeneity tests indicated linkage to FH3 in approximately 27% of these non-LDLR/non-APOB ADH families and implied a fourth locus. Radiation hybrid mapping located four candidate genes at 1p34.1-p32, outside the critical region, showing no identity with FH3. Our results show that ADH is genetically more heterogeneous than conventionally accepted.

Adult↗
PubMed1998

[Value of multidisciplinary consultation in diagnosis and survival of Marfan syndrome].

OBJECTIVES: To facilitate diagnosis, define a strategy for prevention and treatment and obtain further insight concerning Marfan's disease, we conducted a series of multidisciplinary consultations in French clinics. PATIENTS AND METHODS: Five specialists (a genetics specialist, a pediatrician or a rheumatologist, an ophthalmologist, and a psychologist) saw all the patients successively in the same clinic. A synthesis of the clinical files was prepared for analysis. Since the first consultation on 1 January 1995 and the study end on 30 June 1997, 494 patients (67% adults) participated in primary consultations, 143 were seen at follow-up consultations. RESULTS: The diagnosis of Marfan's disease was affirmed in 41% of the patients, disaffirmed in 48% and uncertain in 11%. Among the Marfan's patients, 75% were seen again within the framework of a multidisciplinary follow-up consultations. Annual work-up included cardiology (echocardiography with measurement of the proximal aorta diameter in search for indication for beta-blocker therapy or preventive valve replacement), ophthalmology (lens, retina) and rheumatology examinations (skeletal involvement). CONCLUSION: Early diagnosis and rigorous follow-up can help prevent ocular and cardiac complications in Marfan's disease. The multidisciplinary approach provides more precise data for diagnosis and possible phenotype-genotype correlations.

Adult↗
PubMed1998

Marfan Database (third edition): new mutations and new routines for the software.

The Marfan database is a software that contains routines for the analysis of mutations identified in the FBN1 gene that encodes fibrillin-1. Mutations in this gene are associated not only with Marfan syndrome but also with a spectrum of overlapping disorders. The third version of the Marfan database contains 137 entries. The software has been modified to accommodate four new routines and is now accessible on the World Wide Web at http://www.umd.necker.fr

Computer Communication Networks↗
PubMed1998

LDLR Database (second edition): new additions to the database and the software, and results of the first molecular analysis.

Mutations in the LDL receptor gene (LDLR) cause familial hypercholesterolemia (FH), a common autosomal dominant disorder. The LDLR database is a computerized tool that has been developed to provide tools to analyse the numerous mutations that have been identified in the LDLR gene. The second version of the LDLR database contains 140 new entries and the software has been modified to accommodate four new routines. The analysis of the updated data (350 mutations) gives the following informations: (i) 63% of the mutations are missense, and only 20% occur in CpG dinucleotides; (ii) although the mutations are widely distributed throughout the gene, there is an excess of mutations in exons 4 and 9, and a deficit in exons 13 and 15; (iii) the analysis of the distribution of mutations located within the ligand-binding domain shows that 74% of the mutations in this domain affect a conserved amino-acid, and that they are mostly confined in the C-terminal region of the repeats. Conversely, the same analysis in the EGF-like domain shows that 64% of the mutations in this domain affect a non-conserved amino-acid, and, that they are mostly confined in the N-terminal half of the repeats. The database is now accessible on the World Wide Web at http://www.umd.necker.fr

Computer Communication Networks↗