Theses and Dissertations

Issuing Body

Mississippi State University


Swiderski, Cyprianna

Committee Member

Bailey, Hart

Committee Member

Pasquli, Marzia

Committee Member

McLaughlin, Ron

Committee Member

Burgess, C. Shane

Date of Degree


Document Type

Graduate Thesis - Open Access


Veterinary Medical Science

Degree Name

Master of Science


College of Veterinary Medicine


Department of Clinical Sciences


Hereditary equine regional dermal asthenia (HERDA) is a recessive connective tissue disorder of Quarter Horse lineages. This study correlates previously identified decreases in skin tensile strength in HERDA with abnormal dermal collagen cross linking patterns that are also identified in urine from HERDA horses. Dermal collagen from HERDA horses has significantly less pyridinoline and significantly more deoxypyridinoline than control or carriers. Concentrations of hydroxylysine, the rate limiting substrate for these crosslinks were significantly lower in HERDA versus control and carriers. These characteristics of HERDA skin parallel humans with a similar syndrome of skin fragility, Ehlers Danlos Syndrome TypeVIA. This is the first biochemical evidence explaining the clinical skin fragility that characterizes HERDA and suggests that altered collagen lysine metabolism may be physiologically relevant to the clinical manifestation of HERDA. Evaluations of mature scars indicate that lesion and nonlesioned skin should not be viewed as biologically equivalent in HERDA investigations.



lysylpyridinoline||cyclophilin B||hydroxylysine||collagen crosslinking||healin||collagen||Equine||Horse||HERDA||HC||Hereditary equine regional dermal asthenia||pyridinium crosslinks||pyridinoline||hydroxylysylpyridinoline||deoxypyridinolone||PPIB||peptidyl-prolyl cis trans isomeraase