Williamson, Magali Patricia;
(1992)
The molecular genetics of fucosidosis.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Fucosidosis is a rare, autosomal recessive lysosomal storage disease resulting from a deficiency of α-L-fucosidase. The molecular basis of fucosidosis was investigated in six unrelated patients. The residual α-L-fucosidase activity in extracts of fibroblasts, leukocytes and plasma has been characterised and the cross reacting immunological material (CRIM) against human α-L-fucosidase determined using a two antibody sandwich ELISA technique. Four of the patients had negligible α-L-fucosidase activity and very low CRIM levels, which is typical of fucosidosis patients. Typical patterns of storage products were also seen in urine of these patients by thin layer chromatography (TLC). One atypical patient had intermediate activity and intermediate CRIM. The α-L-fucosidase activity in the sixth patient increased from low levels at age two years to control levels at ten years of age. CRIM levels were above that of controls. This atypical patient also had a different pattern of storage products in urine from that typically seen in fucosidosis or control urine. Analysis of DNA extracted from fibroblasts or lymphocytes revealed that none of the six patients have either of the two previously described fucosidosis-causing mutations. The DNA was haplotyped by two previously described RFLP's observed with Pvu11 and Bg11 restriction enzymes. Southern blotting also showed that none of the patients had any gross gene alterations such as large insertions, deletions or rearrangements. The products of amplification by PCR of exon 8 and flanking regions from all six patients were analysed by mismatch analysis and direct sequencing. No mutations were found in this region. A mutation in the highly conserved donor splice site sequence of intron 5 was identified in one Asian patient. The G-> A transition at the first nucleotide of intron 5 presumably results in aberrant mRNA splicing. The mutation generates a new Taq1 site and cosegregates with the mutant allele in the family of the patient, as determined by enzyme activity. Canine fucosidosis can be used as a model for the human disease. The α-L-fucosidase activity, storage products and mRNA expression was characterised in two fucosidosis dogs. DNA from affected dogs and controls was used by Southern blotting with human cDNA fucosidase probes with the aim of detecting RFLPs. A restriction map of the canine gene was constructed and one RFLP was found with Xba1, which did not segregate with the disease. Mannose-binding protein is a mammalian lectin with a role in host defence. A human liver cDNA library was screened with rat MBP-C cDNA with the aim of isolating the human MBP sequence.
Type: | Thesis (Doctoral) |
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Qualification: | Ph.D |
Title: | The molecular genetics of fucosidosis |
Open access status: | An open access version is available from UCL Discovery |
Language: | English |
Additional information: | Thesis digitised by ProQuest. |
Keywords: | Biological sciences |
URI: | https://discovery.ucl.ac.uk/id/eprint/10120571 |
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