Whole-genome scan identifies quantitative trait loci for chronic pastern dermatitis in German draft horses

Abstract

Chronic pastern dermatitis (CPD), also known as chronic progressive lymphedema (CPL), is a skin disease that affects draft horses. This disease causes painful lower-leg swelling, nodule formation, and skin ulceration, interfering with movement. The aim of this whole-genome scan was to identify quantitative trait loci (QTL) for CPD in German draft horses. We recorded clinical data for CPD in 917 German draft horses and collected blood samples from these horses. Of these 917 horses, 31 paternal half-sib families comprising 378 horses from the breeds Rhenish German, Schleswig, Saxon-Thuringian, and South German were chosen for genotyping. Each half-sib family was constituted by only one draft horse breed. Genotyping was done for 318 polymorphic microsatellites evenly distributed on all equine autosomes and the X chromosome with a mean distance of 7.5 Mb. An across-breed multipoint linkage analysis revealed chromosome-wide significant QTL on horse chromosomes (ECA) 1, 9, 16, and 17. Analyses by breed confirmed the QTL on ECA1 in South German and the QTL on ECA9, 16, and 17 in Saxon-Thuringian draft horses. For the Rhenish German and Schleswig draft horses, additional QTL on ECA4 and 10 and for the South German draft horses an additional QTL on ECA7 were found. This is the first whole-genome scan for CPD in draft horses and it is an important step toward the identification of candidate genes.

Genetic parameters for chronic progressive lymphedema in Belgian Draught Horses

“…; Mittmann et al . ), and early detection is not yet possible. The age of the horse is crucial to distinguish affected from non‐affected individuals, which is in correspondence with the results obtained in German draught horses (aged at least 2.5 years) (Wallraf et al .…”

“…Heritability coefficients (SE) for the occurrence (yes/no) of clinical CPD symptoms averaged 0.22 (0.04) in six German draught horse breeds, ranging from 0.17 (0.07) to 0.51 (0.32) (Wallraf 2003). One of those breeds, the Rhenish German Draught Horse, was founded on Belgian Draught Horses imported at the end of the 19th Century (Aberle et al 2004), so that 34% of the ancestors are estimated to be of Belgian Draught Horse origin (Mittmann et al 2010). This supports the assumption of a genetic CPL susceptibility in the Belgian Draught and other related populations worldwide, for example the American Belgian, the Shire and the Clydesdale (De Cock et al 2003).…”

“…), so that 34% of the ancestors are estimated to be of Belgian Draught Horse origin (Mittmann et al . ). This supports the assumption of a genetic CPL susceptibility in the Belgian Draught and other related populations worldwide, for example the American Belgian, the Shire and the Clydesdale (De Cock et al .…”

Combined decongestive therapy including equine manual lymph drainage to assist management of chronic progressive lymphoedema in draught horses

“…Until potential underlying genetic factors of CPL can be identified to further characterise the exact pathomechanisms of CPL (Momke and Distl 2007a,b; Young et al . 2007; Mittmann et al . 2009), CDT will help in keeping affected horses in better health and hence, prolong their lives.…”

“…In conclusion, this pilot study presents evidence that CDT offers a promising tool for the management of horses affected with CPL, a condition for which there is currently no cure. Until potential underlying genetic factors of CPL can be identified to further characterise the exact pathomechanisms of CPL (Momke and Distl 2007a,b;Young et al 2007;Mittmann et al 2009), CDT will help in keeping affected horses in better health and hence, prolong their lives. A more extensive study is warranted to evaluate the full potential of CDT.…”