The occurrence of dermatosparaxis in a commercial Drakensberger cattle herd in South Africa : article

D.E Holm,C.K Harper,E Van Wilpe,N.M Duncan

doi:10.4102/jsava.v79i1.235

Abstract

Dermatosparaxis is a heritable collagen dysplasia causing skin extensibility and fragility. In Belgian Blue cattle this mutation has been described as a 3 base pair (bp) change followed by a 17bp deletion in the gene coding for procollagen 1 N-Proteinase (pNPI). An outbreak in a commercial Drakensberger herd in South Africa followed the introduction in late 2000 of a 3-year-old bull that developed skin lesions in 2001 and was culled in 2002. Some of his offspring were similarly affected, 1 of which was kept as a breeding bull after his sire's death. Two affected calves were referred to the Onderstepoort Veterinary Academic Hospital in October 2005. Detailed examination revealed only skin abnormalities limited to the lateral extremities of the thorax, abdomen and pelvis, viz. either acute lacerations of varying sizes, slow healing defects or thin scars in chronic cases. During a subsequent farm visit, 13 animals with similar wounds were seen in the herd of 146 animals. Electron microscopic examination of skin biopsies revealed haphazard arrangement and loose packing of dermal collagen fibrils within collagen fibres. The fibrils showed size variation and slightly irregular outlines on cross-section, consistent with mild dermatosparaxis. DNA samples of affected calves were analysed using primers designed to amplify the region of the pNPI gene that contained the mutation described in Belgian Blue cattle, but this mutation could not be demonstrated in any of the animals tested. It is concluded that a form of dermatosparaxis with a different gene mutation from that described in Belgian Blue cattle exists in Drakensberger cattle in South Africa. This possibly also explains the milder and more delayed clinical signs and the milder dermal collagen ultrastructural abnormalities.

Highlights

Dermatosparaxis, known as cutaneous asthenia or Ehlers– Danlos syndrome, is a heritable collagen dysplasia causing hyperextensibility and fragility of the skin
The Odds Ratio (OR) for males compared to females was 1.45
0038-2809 Tydskr.S.Afr.vet.Ver. (2008) 79(1): 19–24 similarities to dermatosparaxis in other breeds and species and given that the age groups affected by the condition coincided with the introduction of affected bulls in the herd, as well as fairly low prevalence of skin lesions in the herd (

Summary

Introduction

Dermatosparaxis (tearing of skin), known as cutaneous asthenia or Ehlers– Danlos syndrome, is a heritable collagen dysplasia causing hyperextensibility and fragility of the skin. The condition has been known in humans since the 17th century, and was first described as a collagen abnormality by Ehlers (Denmark, 1901) and Danlos (France, 1908)[17]. This autosomal recessive genetic defect has been reported in humans, dogs, mink, cattle, sheep, cats and horses[17], but in South Africa only in humans and white Dorper sheep[16]. Cattle breeds known to be affected include Belgian Blue, Holstein, aDepartment of Production Animal Studies, bElectron Microscopy Unit, cVeterinary Genetics Laboratory, dSection of Pathology, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.

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