Show simple item record

dc.contributor.authorPiripi, Susan Amanda
dc.date.accessioned2009-05-04T21:20:14Z
dc.date.availableNO_RESTRICTIONen_US
dc.date.available2009-05-04T21:20:14Z
dc.date.issued2008
dc.identifier.urihttp://hdl.handle.net/10179/800
dc.description.abstractChondrodysplasia of Texel sheep is a newly described recessively inherited disorder distinct from other chondrodysplasias described in sheep. Phenotypically normal at birth, affected lambs develop microscopic lesions as early as 9 days of age, and usually demonstrate gross deformities and markedly reduced rates of bone growth by 2 to 3 weeks. Individual bone growth rates are most severely affected in the proximal bones of the forelimbs. Chondrodysplastic lambs typically have short stature, angular limb deformities, a barrel-shaped chest and a wide-based stance. Gross lesions include tracheal narrowing and contortion, enlarged costochondral junctions, and erosion of articular cartilage in major limb joints. Microscopic lesions are confined to hyaline cartilage, and are characterised by degeneration of the interterritorial matrix and dense perichondrocytic rings consisting predominantly of type VI collagen. These lesions are identical in appearance to those in achondrogenesis 1b and diastrophic dysplasia, two diseases caused by defects of the diastrophic dysplasia sulphate transporter (DTDST) in human beings. An investigation to measure the uptake of radiolabelled sulphate by dermal fibroblasts in vitro did not provide evidence of a defect in the DTDST in chondrodysplastic Texel sheep. A linkage disequilibrium study of ovine chromosomes 1, 5, 6, 13 and 22 using microsatellite DNA markers was unable to identify evidence of a mutation causing this form of chondrodysplasia. Capillary electrophoresis of unsaturated chondroitin sulphate disaccharides demonstrated a relative reduction in the ratio of chondroitin 4-sulphate to chondroitin 6-sulphate in affected animals of all ages. This biochemical feature enables the potential determination of the phenotype of newborn lambs prior to the emergence of gross or microscopic lesions. The pathology of the disease, combined with the findings of the genetic, biochemical and in vitro studies, suggest that a mutation may be present in the CHST11 gene. This gene is a good candidate for future studies aimed at discovering the genetic defect in chondrodysplasia of Texel sheep and developing a test to identify heterozygous animals.en_US
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectChondrodysplasiaen_US
dc.subjectTexel sheepen_US
dc.subjectGenetic defectsen_US
dc.subjectInherited diseasesen_US
dc.subject.otherFields of Research::300000 Agricultural, Veterinary and Environmental Sciences::300500 Veterinary Medicine::300506 Pathologyen_US
dc.titleChondrodysplasia of Texel sheep : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealanden_US
dc.typeThesisen_US
thesis.degree.disciplineVeterinary pathologyen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US


Files in this item

Icon
Icon
Icon

This item appears in the following Collection(s)

Show simple item record