Hereditary equine regional dermal asthenia ("hyperelastosis cutis") in 50 horses: clinical, histological, immunohistological and ultrastructural findings.
Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin and shortened collagen fibres arranged in clusters in the deep dermis was suggestive of the disease. Trichrome, acid orcein-Giemsa and immunohistochemical stains for collagens I and III showed no consistent abnormalities compared to control horses; an increase in elastic fibres was not a consistent finding. Electron microscopy showed no abnormalities in the periodicity of the collagen bundles; neither orientation nor variation of cross-section diameter of the collagen fibrils differentiated control from affected horses. The diagnosis of HERDA relies on clinical presentation, but may be supported by suggestive (although not pathognomonic) histopathological lesions.
White
Stephen D
SD
Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. sdwhite@ucdavis.edu
Affolter
Verena K
VK
Bannasch
Danika L
DL
Schultheiss
Patricia C
PC
Hamar
Dwayne W
DW
Chapman
Phillip L
PL
Naydan
Diane
D
Spier
Sharon J
SJ
Rosychuk
Rod A W
RA
Rees
Christine
C
Veneklasen
Gregg O
GO
Martin
Alondra
A
Bevier
Diane
D
Jackson
Hilary A
HA
Bettenay
Sonya
S
Matousek
Jennifer
J
Campbell
Karen L
KL
Ihrke
Peter J
PJ
D000818:Animals; D015331:Cohort Studies; D003937:Diagnosis, Differential; D004535:Ehlers-Danlos Syndrome / Q000175:diagnosis / Q000662:veterinary*; D005260:Female; D020022:Genetic Predisposition to Disease; D006734:Horse Diseases / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D010375:Pedigree; D011446:Prospective Studies; D012189:Retrospective Studies; D012867:Skin / Q000473:pathology / Q000648:ultrastructure