Genetic risk factors for osteochondrosis in various horse breeds

Abstract

Osteochondrosis (OC) is an injury to cartilage canals with a following necrosis in the growth cartilage, from there it can develop to osteochondrosis dissecans (OCD). Due to its high impact in the equine industry, new insights into predisposing factors and potential high-risk genetic variants are warranted. This article reviews advancements in quantitative and molecular genetics in refining estimation of genetic parameters and identifying predisposing genetic loci. Heritabilities were highest for hock OC with estimates at 0.29-0.46 in Hanoverian warmblood and Norwegian trotters, whereas in Thoroughbreds only very low genetic variation seemed to be present in hock OC lesions. Whole genome scans using the Illumina Equine SNP50 or SNP70 Beadchip were performed in Thoroughbred, Standardbred, French and Norwegian trotter, Hanoverian and Dutch warmblood. Validation studies in Spanish Purebred and Hanoverian warmblood horses corroborated OC risk loci on ECA 3, 14, 27 and 29. Particularly, a strong association with hock-OCD was found for a single nucleotide polymorphism (SNP) on horse chromosome (ECA) 3 upstream to the LCORL gene. Gene expression and microRNA analyses may be helpful to understand pathophysiological processes in equine OC and to connect OCD-associated genomic regions with potential candidate genes. Furthermore progress in elucidating the underlying genetic variants and pathophysiological changes in OC may be expected from whole genome DNA and RNA next-generation sequencing studies.

Description of a rare osteochondrosis lesion of the medial aspect of the distal intermediate ridge of the tibia in seven Thoroughbred horses (2008‐2018)

“…Most authors agree that some degree of motion disturbance is involved in the development of osteochondrosis/OCD . Clinical signs of these lesions become more evident in young horses with increased training and may lead to a decrease in their performance . Studies have shown that osteochondrosis in young horses affects the growing cartilage of the articular/epiphyseal complex of predisposed joints .…”

“…Clinical signs of these lesions become more evident in young horses with increased training and may lead to a decrease in their performance . Studies have shown that osteochondrosis in young horses affects the growing cartilage of the articular/epiphyseal complex of predisposed joints . The abnormal cartilage can be thickened, collapsed, or fragmented, and may progress to a separated osteochondral flap at specific predilection sites .…”

“…Studies have shown that osteochondrosis in young horses affects the growing cartilage of the articular/epiphyseal complex of predisposed joints . The abnormal cartilage can be thickened, collapsed, or fragmented, and may progress to a separated osteochondral flap at specific predilection sites . The most commonly affected articulations include the tarsus, stifle, and metacarpophalangeal/metatarsophalangeal joints, but the disease has been described in almost every diarthrodial joint in the horse .…”

Fifty years of osteochondrosis

“…Despite earlier hopes that 'the OC gene(s)' would be found, there is now consensus that the genetic basis of OC is polygenic and highly complex. The review by Naccache et al [10] in this issue of EVJ describes quantitative trait loci (QTLs) shown to be significantly linked to OC in genome-wide studies on not less than 20 of the 33 chromosomes of the horse. A further complicating and most likely related issue is that the genetic contributors to OC may vary with OC at different locations and even in different manifestations of OC at the same location [11].…”

Fifty years of Equine Veterinary Journal

“…It is a complex multifactorial orthopaedic condition that has been extensively reported, but the genetics are still far from being completely understood. The article by Naccahe, Metzger and Distl considers the current position of genetic and genomic knowledge by reviewing the quantitative and molecular genetics involved . They feel that gene expression may be helpful to understand pathophysiological processes in OC and to connect OC‐associated genomic regions with potential candidate genes.…”