Identification of the gene and validation likely disease causing variants causing dermatosparaxis in Merino Sheep

Hughes, Patrick
Sydney University


An Abstract or a Thesis was not submitted. The following is an extract from the application.

Dermatosparaxis or Ehlers Danlos disease is a recessive hereditary disease that effects collagen production. The disease causes thinning of the skin with reduced strength and elasticity which can lead to tearing of the skin. This disease has previously been described in humans and other animal species, including Dorper sheep. In Dorper sheep likely disease causing mutations have been described in the ADAMTS2 gene (Zhou et al. 2012, Monteagudo et al. 2015, Joller et al. 2017). More recently the disease has been reported in at least two flocks in Australian Merino sheep and appears to have serious animal welfare implications in affected animals.

Aim of this study is to map the disease and identify the disease causing variant in Merino sheep to allow effective management

Samples for histopathology and DNA extraction of affected Merino sheep and obligate carriers have been collected from two properties in NSW.
DNA of one affected sheep from the 1st property has been whole genome sequenced in a collaboration with Prof Tosso Leeb from Switzerland and is currently analysed with a focus on genetic variants in the candidate gene ADAMTS2. A much larger sample set has been provided more recently from the second property.

Any likely disease causing variants identified in the whole genome sequencing data will be validated in the larger cohourt of animals.
If no likley disease causing variant will be identified in the candidate gene, SNP chip genotyping and homozygosity mapping will be conducted on the extended sample set to map the disease. The mapping inforamtion will than be used to reanalyse the existing whole genome sequencing data.
If a disease causing variant is identified and validated a diagnostic test will be developped and the information will be published to allow effective implementation of DNA testing for industry.