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Y Boyd

Publications and source records attributed to Y Boyd.

85 records · Page 5Linked to original sources
PubMed1987

Molecular heterogeneity of translocations associated with muscular dystrophy.

Individual translocation chromosomes from six girls suffering from Duchenne or Becker muscular dystrophy (DMD or BMD) have been isolated in human-mouse somatic cell hybrids. DNA prepared from these hybrids was probed with sequences physically close to the locus; these include a junction fragment from the site of the X:21 translocation (pXJ1) and subclones from the pERT 87 (DXS164) region which are absent in a minority of male DMD patients. Both sets of sequences mapped within the area defined by the translocation breakpoints, confirming their close proximity to the DMD and BMD loci. Furthermore, the X chromosome breakpoints of the translocations can be divided into three categories depending upon their position in relation to the sequences recognised by pXJ1 and pERT 87. The genomic target disrupted by the translocations examined here is a minimum of 176 kb.

Chromosome Mapping↗
PubMed1987

Characterization and use of somatic cell hybrids with interspecific translocations involving the human X chromosome.

Two hybrid cell lines, whose only human material was a portion of the X translocated on to a mouse chromosome, have been characterized by cytogenetics, in situ hybridization and Southern blotting. In one hybrid (HORL911R8B) the region Xpter to Xq2(2-4) was identified. In the other (PIP) the single human fragment was found to contain sequences from two separate X chromosomal regions (corresponding approximately to Xp11.4-Xp22.1 and Xq26-Xqter). These two hybrids in combination with a third (WAG 8) retaining Xqter to Xp21 as a human X-autosome translocation chromosome, form a mapping panel for rapid subregional assignments to the human X chromosome. This mapping panel has been used to provide information about the order of DNA sequences derived from the X chromosome and to provide an assignment for an anonymous DNA segment, M201 gamma, to Xp11.4-Xp21.1.

Animals↗
PubMed1987

Localisation of Y chromosome sequences in normal and 'XX' males.

Three unique sequences derived from the Y chromosome have been mapped within the human genome. A Y specific sequence DYS20 is localised to Yq11.2. DXYS25 and DXYS27 are both X-Y homologous sequences which map to the Y short arm and to Xq21. DXYS25 maps more distally than DXYS27, on the Y short arm and on the X long arm. Y specific restriction fragments for these two sequences are shown to be present in the genome of two XX males, and an aberrant signal for DXYS25 is demonstrated at the tip of an X chromosome short arm in one XX male by in situ hybridisation. The implications of these findings for the location of the testis determining factor are discussed.

Chromosome Deletion↗
PubMed1986

Cytogenetic heterogeneity of translocations associated with Duchenne muscular dystrophy.

Lymphoblastoid cell lines have been established from nine female patients with Duchenne muscular dystrophy who had previously been reported to have chromosome translocations with breakpoints in the Xp21 region. A detailed cytogenetic comparison of prometaphase chromosomes in these cell lines revealed that six of the translocations had X chromosome breakpoints in the sub-band Xp212 and that one further breakpoint could be assigned to either Xp212 or Xp213. These findings confirm and extend previous observations and provide strong evidence for Xp212 as the site of the Duchenne and Becker loci. For the remaining two translocations the simplest explanation for the observed banding pattern is that the X chromosome breakpoint lies a few thousand kilobases away, in the sub-band Xp211. Other explanations which assume breaks in Xp212 combined with complex local chromosome rearrangements are also presented. It is also possible that the altered banding pattern in these two cases is due to the influence of local sequences on the staining or uncoiling properties of the chromatin.

Female↗
PubMed1986

Muscular dystrophy in girls with X;autosome translocations.

Twenty known cases of X;autosome translocations with breakpoints at Xp21 associated with Duchenne or Becker muscular dystrophy in girls are reviewed. The variable severity described for different persons may reflect differences in X inactivation or in the nature of the genomic target disrupted. High resolution cytogenetic studies on 12 cases indicate breakpoints on the X chromosome at Xp21.1 or Xp21.2. Translocation chromosomes from several of these cases have been isolated in human/mouse somatic cell hybrids. Molecular heterogeneity in the breakpoint positions has been established by probing DNA from these hybrids with a range of cloned sequences known to be located within, or closely linked to, the Duchenne region. The minimum separation between the most distal and the most proximal breakpoints is 176 kb suggesting that, if a single gene is involved, it must be large. Alternatively, the translocations may affect different genes, or confer alterations to regulatory sequences which operate at a distance.

Chromosome Banding↗
PubMed1986

Duchenne muscular dystrophy in one of monozygotic twin girls.

Monozygotic twin girls are reported, one of whom has the typical clinical features of Duchenne muscular dystrophy despite a normal female karyotype. Although certain features of the biopsy were atypical, the clinical diagnosis was supported by persistent markedly raised blood creatine kinase levels and findings typical of DMD on electromyography and magnetic resonance spectroscopy. Analysis of an X linked DNA polymorphism in 16 independent somatic cell hybrids made between cells derived from each girl and a mouse line suggest that in one twin only the maternal X chromosome is active, whereas in the other the active X was paternally derived. More data are needed to exclude sampling error. These preliminary experimental results support the hypothesis that both girls are heterozygous for Duchenne muscular dystrophy. X inactivation, by chance, resulted in two contrasting cell masses with different active X chromosomes. This segregation was followed by, and may even have resulted in, twinning into a female pair, one normal and one with the full clinical features of the disease.

Biopsy↗
PubMed1984

Assignment of the haemophilia B (factor IX) locus to the q26-qter region of the X chromosome.

Two independent approaches have provided an assignment for the factor IX (Haemophilia B) locus to Xq26-qter, the distal region of the X chromosome long arm. Cloned DNA sequences of the gene were hybridized to restriction enzyme digests of DNA prepared from a series of somatic cell hybrids containing different X-chromosomal regions and also in situ to prepared metaphase chromosomes.

Animals↗
PubMed1977

Assignment of the DIA1 locus to chromosome 22.

Human/rodent hybrid cell cultures were examined for the presence of DIA1 and other marker enzymes. Many of these hybrids were also analysed for human chromosomes. Complete concordance was found only with chromosome 22.

Animals↗
PubMedDate not supplied

The parental origin of de novo X-autosome translocations in females with Duchenne muscular dystrophy revealed by M27 beta methylation analysis.

The parental origin of 3 de novo X-autosome translocations in females with Duchenne Muscular Dystrophy (DMD) was studied by means of methylation analysis using the X-linked probe M27 beta. In all three the translocation was found to be paternal in origin. The parental origin of X-autosome translocations in females with and without DMD is compared with other structural abnormalities of the X and with autosomal translocations.

Animals↗
PubMedDate not supplied

Localization of the properdin factor complement locus Pfc to band A3 on the mouse X chromosome.

The locus for properdin (properdin factor complement, Pfc), a plasma glycoprotein, has been mapped to band A3 of the mouse X chromosome by in situ hybridization to metaphase spreads containing an X;2 Robertsonian translocation. The X-linkage of the locus has also been confirmed by analysis of Mus musculus x Mus spretus interspecific crosses. The XA3 localization for Pfc places it in the chromosomal segment conserved between man and mouse which is known to contain at least six other homologous loci (Cybb, Otc, Syn-1 Maoa, Araf, Timp).

Animals↗
PubMedDate not supplied

Gene deletions in patients with haemophilia B and anti-factor IX antibodies.

Christmas disease, or haemophilia B, is an inherited X-linked haemorrhagic disease which at present occurs in 798 known cases in the United Kingdom, corresponding to a frequency of about 1 in 30,000 males. Patients are deficient in the intrinsic clotting factor IX and are treated by replacement of this protein prepared from pooled plasma obtained from normal individuals. Occasionally treatment is complicated by the appearance of specific anti-factor IX antibodies. It seemed to us that this might be due to the absence of 'self' factor IX causing the immune system to regard the infused normal factor IX as foreign. The absence of all or part of the factor IX gene was an obvious possible reason for this, which we have now tested using our previously isolated gene probe. We have found four patients with gross gene defects.

Autoantibodies↗
PubMedDate not supplied

Structure and chromosomal localization of chicken CD5.

CD5 is a transmembrane glycoprotein on all T cells and on a subpopulation of B cells. Based on the analysis of chicken CD5-cDNA we have previously shown that the structure of the CD5 protein is conserved between species. Here we report the isolation and chromosomal mapping of the chicken CD5 gene. The gene spans 3.4 kb and is extremely compact with a high GC-nucleotide content. There are 10 exons and the introns are spliced out similarly to those in the human CD5 gene. Each of the three extracellular scavenger receptor cysteine-rich (SRCR) domains is encoded as an exon of its own, as is the proline-rich hinge region that separates the first two membrane-distal SRCR domains. The fluorescence in situ hybridization (FISH) technique was used to map the gene to chromosome five. This is the first report describing the organization of the CD5 gene from a nonmammalian species.

Animals↗