Canine diffuse idiopathic skeletal hyperostosis

A Multicenter Allelic Analysis of Diffuse Idiopathic Skeletal Hyperostosis: Nature Versus Nurture?

BACKGROUND

Diffuse idiopathic skeletal hyperostosis (DISH) is an incompletely defined disease process with no known unifying pathophysiological mechanism.

OBJECTIVE

To our knowledge, no genetic studies have been performed in a North American population. To summarize genetic findings from previous studies and to comprehensively test for these associations in a novel and diverse, multi-institutional population.

METHODS

Cross-sectional, single nucleotide polymorphism (SNP) analysis was performed in 55 of 121 enrolled patients with DISH. Baseline demographic data were available on 100 patients. Based on allele selection from previous studies and related disease conditions, sequencing was performed on COL11A2, COL6A6, fibroblast growth factor 2 gene, LEMD3, TGFB1, and TLR1 genes and compared with global haplotype rates.

RESULTS

Consistent with previous studies, older age (mean 71 years), male sex predominance (80%), a high frequency of type 2 diabetes (54%), and renal disease (17%) were observed. Unique findings included high rates of tobacco use (11% currently smoking, 55% former smoker), a higher predominance of cervical DISH (70%) relative to other locations (30%), and an especially high rate of type 2 diabetes in patients with DISH and ossification of the posterior longitudinal ligament (100%) relative to DISH alone (100% vs 47%, P < .001). Compared with global allele rates, we found higher rates of SNPs in 5 of 9 tested genes ( P < .05).

CONCLUSION

We identified 5 SNPs in patients with DISH that occurred more frequently than a global reference. We also identified novel environmental associations. We hypothesize that DISH represents a heterogeneous condition with both multiple genetic and environmental influences.

Spinal fracture in a dog with diffuse idiopathic skeletal hyperostosis

A six-year-old, spayed female Weimaraner dog was first presented with the complaint of hindlimb paresis and then hindlimb paralysis two years later after colliding with a tree. Radiographs and computed tomography revealed spinal fractures at lumbar vertebrae (L)2-3 and at L4-5. In addition, the spinal column was affected by new bone formation along the vertebral bodies, bridging the disc spaces, as seen in diffuse idiopathic skeletal hyperostosis (DISH). Open reduction and internal fixation was achieved with standard vertebral body plating. This is the first report of DISH-associated spinal fractures after minor trauma in a dog. Surgery resulted in return of the full function after the first, and in improvement of neurologic function after the second incident.

Combined approach for finding susceptibility genes in DISH/chondrocalcinosis families: whole-genome-wide linkage and IBS/IBD studies

Twelve families with exuberant and early-onset calcium pyrophosphate dehydrate chondrocalcinosis (CC) and diffuse idiopathic skeletal hyperostosis (DISH), hereafter designated DISH/CC, were identified in Terceira Island, the Azores, Portugal. Ninety-two (92) individuals from these families were selected for whole-genome-wide linkage analysis. An identity-by-descent (IBD) analysis was performed in 10 individuals from 5 of the investigated pedigrees. The chromosome area with the maximal logarithm of the odds score (1.32; P=0.007) was not identified using the IBD/identity-by-state (IBS) analysis; therefore, it was not investigated further. From the IBD/IBS analysis, two candidate genes, LEMD3 and RSPO4, were identified and sequenced. Nine genetic variants were identified in the RSPO4 gene; one regulatory variant (rs146447064) was significantly more frequent in control individuals than in DISH/CC patients (P=0.03). Four variants were identified in LEMD3, and the rs201930700 variant was further investigated using segregation analysis. None of the genetic variants in RSPO4 or LEMD3 segregated within the studied families. Therefore, although a major genetic effect was shown to determine DISH/CC occurrence within these families, the specific genetic variants involved were not identified.

Vertebral Adaptations to Large Body Size in Theropod Dinosaurs

Rugose projections on the anterior and posterior aspects of vertebral neural spines appear throughout Amniota and result from the mineralization of the supraspinous and interspinous ligaments via metaplasia, the process of permanent tissue-type transformation. In mammals, this metaplasia is generally pathological or stress induced, but is a normal part of development in some clades of birds. Such structures, though phylogenetically sporadic, appear throughout the fossil record of non-avian theropod dinosaurs, yet their physiological and adaptive significance has remained unexamined. Here we show novel histologic and phylogenetic evidence that neural spine projections were a physiological response to biomechanical stress in large-bodied theropod species. Metaplastic projections also appear to vary between immature and mature individuals of the same species, with immature animals either lacking them or exhibiting smaller projections, supporting the hypothesis that these structures develop through ontogeny as a result of increasing bending stress subjected to the spinal column. Metaplastic mineralization of spinal ligaments would likely affect the flexibility of the spinal column, increasing passive support for body weight. A stiff spinal column would also provide biomechanical support for the primary hip flexors and, therefore, may have played a role in locomotor efficiency and mobility in large-bodied species. This new association of interspinal ligament metaplasia in Theropoda with large body size contributes additional insight to our understanding of the diverse biomechanical coping mechanisms developed throughout Dinosauria, and stresses the significance of phylogenetic methods when testing for biological trends, evolutionary or not.

Diffuse idiopathic skeletal hyperostosis of the spine in a nine-year-old cat

A nine-year-old intact female domestic shorthair cat was evaluated for paraparesis, ataxia and severe spinal hyperaesthesia. Neurological examination indicated a T3-L3 spinal cord segment lesion. Computed tomography of the thoracolumbar and lumbosacral vertebral column was performed. This showed contiguous smooth new bone formation ventral and lateral to the vertebrae extending from the cranial thoracic area to the lumbosacral junction and appearing similar to canine diffuse idiopathic skeletal hyperostosis. There was also marked dorsolateral stenosis of the vertebral canal at the level of T4-T5 because of degenerative changes of the facet joints. To the authors' knowledge, this is the first published report of feline diffuse idiopathic skeletal hyperostosis.

Diffuse idiopathic skeletal hyperostosis with prominent appendicular bone proliferation in a dog

This report described radiographic and CT features of atypical diffuse idiopathic skeletal hyperostosis in a 5 year-old, female Shih-tzu showing marked proliferative bone lesions in the appendicular skeleton with minor spinal changes. Continuous or flowing bony bridge formation of vertebrae is used as the gold standard for diagnosing diffuse idiopathic skeletal hyperostosis. However, this criterion seems not to be suitable for appendicular type diffuse idiopathic skeletal hyperostosis, as in the present case. Diffuse idiopathic skeletal hyperostosis is a progressive skeletal disease, and thus, enthesophytosis and the multiple bony proliferations at insertion sites of ligaments and tendons to appendicular bones in a lamellar or trabecular pattern were considered diagnostic features of the appendicular type of diffuse idiopathic skeletal hyperostosis.

Imaging diagnosis-an atypical presentation of diffuse idiopathic skeletal hyperostosis (dish) in a dog

A 10-year-old female spayed Dalmatian was evaluated for progressive cervical scoliosis and stiffness. This imaging report describes the imaging and postmortem findings for this patient. A diagnosis of an atypical manifestation of diffuse idiopathic skeletal hyperostosis (DISH) was made based on imaging and additional diagnostics. This report serves to increase awareness of DISH in the veterinary community, as well as to describe a unique presentation of the disease with atypical lesion distribution and severity. In addition, this report contrasts the pathophysiology and imaging characteristics of DISH with spondylosis deformans, which can appear comparable radiographically.

Spondylosis deformans and diffuse idiopathic skeletal hyperostosis (dish) resulting in adjacent segment disease

Spondylosis deformans and diffuse idiopathic skeletal hyperostosis (DISH) are usually incidental findings and in most dogs are either asymptomatic or associated with mild clinical signs. Severe spondylosis deformans and DISH can result in complete bony fusion of consecutive vertebral segments. One of the recognised complications following vertebral fusion in human patients is the development of adjacent segment disease, which is defined as degenerative changes, most commonly degenerative intervertebral disc disease, in the mobile vertebral segment neighboring a region of complete vertebral fusion. A similar syndrome following cervical fusion in dogs has been termed the domino effect. The purpose of this retrospective study was to investigate the hypothesis that vertebral fusion occurring secondary to spondylosis deformans or DISH in dogs would protect fused intervertebral disc spaces from undergoing degeneration, but result in adjacent segment disease at neighbouring unfused intervertebral disc spaces. Eight dogs with clinical signs of thoracolumbar myelopathy, magnetic resonance imaging of the thoracolumbar vertebral column, and spondylosis deformans or DISH producing fusion of > or = 2 consecutive intervertebral disc spaces were evaluated. Vertebral fusion of > or = 2 consecutive intervertebral disc spaces was correlated (P = 0.0017) with adjacent segment disease at the neighbouring unfused intervertebral disc space. Vertebral fusion appeared to protect fused intervertebral disc spaces from undergoing degeneration (P < 0.0001). Adjacent segment disease should be considered in dogs with severe spondylosis deformans or DISH occurring in conjunction with a thoracolumbar myelopathy.

The dog as an animal model for DISH?

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic disorder of the axial and peripheral skeleton in humans and has incidentally been described in dogs. The aims of this retrospective radiographic cohort study were to determine the prevalence of DISH in an outpatient population of skeletally mature dogs and to investigate if dogs can be used as an animal model for DISH. The overall prevalence of canine DISH was 3.8% (78/2041). The prevalence of DISH increased with age and was more frequent in male dogs, similar to findings in human studies. In the Boxer breed the prevalence of DISH was 40.6% (28/69). Dog breeds represent closed gene pools with a high degree of familiar relationship and the high prevalence in the Boxer may be indicative of a genetic origin of DISH. It is concluded that the Boxer breed may serve as an animal model for DISH in humans.

Spinal hyperostosis in comparative pathology. A useful approach to the concept

Spinal hyperostosis, an anatomical and radiological concept primarily described in man, is characterized by enthesopathic bony overgrowth on vertebral bodies in the form of spurs or intervertebral bridges. It can also be part of a more diffuse enthesopathic condition, including the appendicular skeleton. These changes are distinct from those of osteoarthrosis. Similar changes can be observed in all kinds of mammals, independent of their type of locomotion (bipodic, quadrumanous, quadrupedic, or aquatic). An anatomical and radiological study is presented of six cases (with histological examination of two dogs and one horse, and observation of macerated specimens of one horse, one equida, and one whale). Comparative pathology allows for a better understanding of the concept of hyperostosis and, even more clearly than in man, this can be distinguished from that of discovertebral pathology although both conditions could be associated in older subjects. The knowledge of spinal hyperostosis in veterinary medicine could--as in man--be of interest to differentiate between this process and other features of vertebral pathology.