Search PubMed⌕ Search

Biomedical subjects

D W Cox

Publications and source records attributed to D W Cox.

At least 73 records · Page 4Linked to original sources
PubMed1994

The immunoglobulin heavy chain and disease association: application to pemphigus vulgaris.

Genes involved in the immune response are generally encoded from a complex cluster of gene segments. Studies of the association of diseases with such genes require well-defined genetic markers throughout the selected region. A set of 15 polymorphic loci that span 1500 kb of the immunoglobulin heavy chain (IGH) complex, 8 in the variable (VH) region and 7 in the constant (CH) region, were selected for the study of disease association. We present a protocol for the use of multiple immunoglobulin heavy chain (IGH) polymorphisms for general application in disease association studies. No microsatellite repeat markers are available for this region. To demonstrate the applicability of this approach, we have examined these IGH polymorphisms in families with individuals affected with pemphigus vulgaris (PV), an autoimmune dermatologic disease. Allele frequencies in 12 patients with PV were compared with those found in their spouses, and with those in a white Canadian control population. A significant difference was found between PV patients and both control groups for the presence of the VH gene VH3f-R4, and possibly for the absence of VH3f-R3, suggesting the possibility of susceptibility factors in these regions. Examination of the frequencies of the IGH region C gamma-haplotypes of PV patients indicated that, while the patients did not differ significantly from their spouses (chi 2 = 1.79), both groups were found to differ significantly from the white Canadian control group (chi 2 = 10.10), emphasizing the importance of matching the ethnic background of controls with that of the patient test group in disease association studies. Unexpectedly, two patients had large deletions of genes in the IGH constant region, which could play a role in the development of PV and require further investigation.

Alleles↗
PubMed1994

Wilson disease and Menkes disease: new handles on heavy-metal transport.

Little is known at the molecular level about the homeostatic control of heavy-metal concentrations in mammals. Recently, however, two human diseases that disrupt copper transport, Menkes disease and Wilson disease, were found to be caused by mutations in two closely related genes, MNK and WND, which encode proteins belonging to the P-type ATPase family of cation transporters. The MNK and WND proteins are unique in having at their amino termini six copies of a sequence that is remarkably similar to sequences previously found in bacterial heavy-metal-resistance proteins and in a P-type ATPase that appears to form part of a bacterial copper homeostatic system. These two human ATPases are the first putative heavy-metal transporters to be discovered in eukaryotes.

Amino Acid Sequence↗
PubMed1994

The LEC rat has a deletion in the copper transporting ATPase gene homologous to the Wilson disease gene.

The Long-Evans Cinnamon (LEC) rat shows similarity to Wilson disease in many clinical and biochemical features. We have cloned cDNAs for the rat gene (Atp7b) homologous to the human Wilson disease gene (ATP7B) and have used them to identify a partial deletion in the Atp7b gene in the LEC rat. The deletion removes at least 900 bp of the coding region at the 3' end, includes the crucial ATP binding domain and extends downstream of the gene. Our results provide convincing evidence for defining the LEC rat as an animal model for Wilson disease. This model will be important for studying liver pathophysiology, for developing therapy for Wilson disease and for studying the pathway of copper transport and its possible interaction with other heavy metals.

Adenosine Triphosphatases↗
PubMed1994

A heat shock gene at 14q22: mapping and expression.

Heat shock proteins (HSP) belong to a family of highly homologous proteins that are encoded by several genes and function as protein chaperones. A number of HSP genes have been described in the major histocompatibility complex (MHC) on chromosome 6. We have cloned and mapped one chromosome 14 HSP gene (HSPA2) using a genomic probe (pH2.3) derived from one of the HSP genes present in the MHC, which was previously shown to also detect sequences on chromosome 14. Screening of a chromosome 14-specific cosmid library yielded one relevant clone that contains an HSP-like sequence, showing a high degree of identity with the HSP genes from the MHC and with HSP70.2 (Hspa2) in the mouse. This new HSP gene is expressed abundantly in muscle, heart, oesophagus and brain, and to a lesser extent in testis. Its localization to 14q22 was established by using a somatic cell hybrid panel and FISH analysis. A pentanucleotide repeat motif, showing seven alleles, was also identified in the cosmid clone.

Amino Acid Sequence↗
PubMed1994

Regional localization of loci on chromosome 14 using somatic cell hybrids.

We have used a panel of human x rodent somatic cell hybrids containing translocations involving chromosome 14 to regionally localize 17 genes and 5 random segments previously mapped to chromosome 14. Each hybrid cell line contains a specific fragment of chromosome 14, with breakpoints at 14q11.2, 14q21, 14q22, 14q24.3 or in two different regions of 14q32.1. The enzyme deficient in glycogen storage disease type VI, liver glycogen phosphorylase (PYGL), has been localized by in situ hybridization to 14q21-->q22, near the q21-->q22 band interface. Four additional genes, chromogranin A (CHGA), myosin (MYH7), tRNA proline 2 (TRP2) and c-FOS (FOS) and four random segments, D14S26, D14S12, D14S14 and D14S13 have been more precisely localized. This study also defines a hybrid cell panel with seven mapping intervals, that will be useful for further physical mapping of new loci.

Animals↗
PubMed1994

Physical and genetic mapping of the serpin gene cluster at 14q32.1: allelic association and a unique haplotype associated with alpha 1-antitrypsin deficiency.

The alpha 1-antitrypsin (PI) gene is part of a cluster of structurally related serine protease inhibitor genes localized at chromosome 14q32.1, a cluster that includes the alpha 1-antichymotrypsin (AACT), protein C inhibitor (PCI), and corticosteroid-binding globulin (CBG) genes and the alpha 1-antitrypsin-like pseudogene (PIL). The order of the genes is refined here by genetic mapping using simple tandem repeat polymorphisms (STRPs) and by physical mapping in YACs. The order of the genes is (centromere)-CBG-PIL-PI-PCI-AACT-(telomere). Analysis of DNA haplotypes comprising STRP and RFLP markers in the serpin genes reveals considerable allelic association throughout the cluster. Furthermore, the common alpha 1-antitrypsin deficiency allele, PI*Z, has a unique DNA haplotype at the CBG, PIL, and PI loci, which extends over 60 kb in 97% of cases and in 44% of cases includes the PCI and AACT loci. This unique haplotype will be of use in examining a number of other diseases, particularly those with an inflammatory component, thought to be associated with alpha 1-antitrypsin deficiency or partial deficiency.

Alleles↗
PubMed1994

Haplotype studies in Wilson disease.

In 51 families with Wilson disease, we have studied DNA haplotypes of dinucleotide repeat polymorphisms (CA repeats) in the 13q14.3 region, to examine these markers for association with the Wilson disease gene (WND). In addition to a marker (D13S133) described elsewhere, we have developed three new highly polymorphic markers (D13S314, D13S315, and D13S316) close to the WND locus. We have examined the distribution of marker alleles at the loci studied and have found that D13S314, D13S133, and D13S316 each show nonrandom distribution on chromosomes carrying the WND mutation. We have studied haplotypes of these three markers and have found that there are highly significant differences between WND and normal haplotypes in northern European families. These findings have important implications for mutation detection and molecular diagnosis in families with Wilson disease.

Base Sequence↗
PubMed1993

Long range restriction mapping of 13q14.3 focused on the Wilson disease region.

The Wilson disease locus (WND) has been mapped by multipoint linkage analysis to a region within 13q14.3 that is flanked proximally by marker D13S31 and distally by marker D13S59 at distances of 0.4 and 1.2 cM, respectively. Long range restriction maps were constructed around these two markers to provide a framework for the detailed physical analysis that will be necessary for the cloning of the gene. The maps, together spanning over 4 Mb, include five newly isolated markers (D13S110, D13S113, D13S194, D13F71S1, and D13S196) and two established markers (D13S56 and D13S25) that were previously localized to 13q14.2-q14.3 using a hybrid panel. Markers D13F71S1 and D13S196 map to the region between D13S31 and D13S59 and will therefore be useful for the isolation of YACs for further molecular studies on Wilson disease.

Animals↗
PubMed1993

Immunoglobulin heavy chain variable region polymorphisms and multiple sclerosis susceptibility.

In addition to the major histocompatibility complex (MHC), genetic susceptibility in multiple sclerosis (MS) appears to be influenced by other loci. A recent study has identified a population association with an immunoglobulin heavy chain variable region polymorphism in the VH2-B5 family, with both familial and sporadic MS patients. We have repeated this association study in a second MS patient group and used two ethnically and geographically matched control groups and the MS patients' unaffected sibs for comparisons. The VH2-B5 polymorphism was found to be over-represented in MS patients when compared to all three control groups. This VH2-B5 association was stronger when the MS patient data were combined with data from our previous study. To further explore the implications of this population association, MS sibships were analyzed for haplotype sharing by identity by descent (IBD) for VH2 and VH3f gene segment polymorphisms. The distribution of haplotype sharing did not differ from that expected based upon random segregation. The data are consistent with the IGVH locus exerting a minor effect perhaps by interacting with other loci to influence MS susceptibility or with genetic heterogeneity and a role for this complex in a subgroup of patients.

Alleles↗
PubMed1993

DNA markers for the diagnosis of Wilson disease.

Wilson disease is an autosomal recessive disorder of copper transport for which the basic defect is unknown. Laboratory diagnosis of Wilson disease is usually made by measuring serum ceruloplasmin concentration, urinary copper excretion, and liver copper concentration. However, discrimination between heterozygotes and patients is sometimes difficult. The gene for Wilson disease has been assigned to chromosome-13 at q14-q21. In this study, 10 markers from the 13q14-13q21 region were investigated in 12 families with a well-established diagnosis, to confirm reported linkage results. Markers from the same region were tested in two additional families, in which a sib of each index case had unclear results with conventional biochemical assays. The linkage results in this study are similar to those of Middle Eastern families, and support the hypothesis of a single disease locus. In the two families studied for diagnostic purposes, the status of 2 presymptomatic sibs was established as affected and 1 as unaffected. This study therefore shows that DNA markers can be used to discriminate between presymptomatic patients and non-affected individuals when biochemical results are equivocal, as long as an index case with Wilson disease of known status is available and markers are informative.

Adolescent↗
PubMed1993

The Wilson disease gene is a putative copper transporting P-type ATPase similar to the Menkes gene.

Wilson disease (WD) is an autosomal recessive disorder of copper transport, resulting in copper accumulation and toxicity to the liver and brain. The gene (WD) has been mapped to chromosome 13 q14.3. On yeast artificial chromosomes from this region we have identified a sequence, similar to that coding for the proposed copper binding regions of the putative ATPase gene (MNK) defective in Menkes disease. We show that this sequence forms part of a P-type ATPase gene (referred to here as Wc1) that is very similar to MNK, with six putative metal binding regions similar to those found in prokaryotic heavy metal transporters. The gene, expressed in liver and kidney, lies within a 300 kb region likely to include the WD locus. Two WD patients were found to be homozygous for a seven base deletion within the coding region of Wc1. Wc1 is proposed as the gene for WD.

Adenosine Triphosphatases↗
PubMed1993

Allelic association and linkage studies in Wilson disease.

We have studied 21 families with Wilson disease (WND), using restriction fragment length polymorphisms (RFLPs) in the 13q14.3 region, to measure linkage of these markers to the disease locus. In addition to previously described markers, we include linkage data for a newly isolated marker (D13S86) and an established marker (D13S56), which were previously not placed on the genetic map in the region of the WND locus. Our data, including those from two recombinant families, support the location of WND between the markers D13S31 and D13S59. We have examined the distribution of marker alleles at the loci studied and have found that D13S31 and D13S228, and associated microsatellite marker, show a non-random distribution on chromosomes carrying the WND mutation. The significant linkage disequilibrium indicates that these two markers must be close to the WND locus.

Alleles↗
PubMed1993

Isolation of new probes in the region of the Wilson disease locus, 13q14.2-->q14.3.

A hybrid panel was used to refine the localizations of eight established markers useful for the diagnosis of Wilson disease. Two of the markers, D13S59 and D13S31, that map very close to the Wilson disease locus (WND) were localized to the region 13q14.2-->q14.3. We report the isolation of seven new probes from this region, using two different approaches. First, 16 clones from a chromosome 13-specific library were mapped using the hybrid panel. Three of the clones mapped to 13q14.2-->q14.3. As a second approach, Alu element-mediated PCR (Alu-PCR) was used to generate clones from a hybrid (ICD) that contains the proximal half of chromosome 13 as the only human component. To select for those that potentially mapped within the region 13q14.2-->q14.3, the clones were screened by differential hybridization using the labeled Alu-PCR products from a hybrid (KSF39) that is similar to ICD but has a deletion in the region 13q14.2-->q14.3. The procedure was successful even though KSF39 contains five additional human chromosomes. Six independent clones were selected. Five of these were found to be nonrepetitive, and four were found to map correctly to 13q14.2-->q14.3 when localized using the hybrid panel.

Chromosomes, Human, Pair 13↗