Ehlers-Danlos syndrome (cutaneous asthenia) in a Campbell's dwarf hamster (Phodopus campbelli).

A case of cutaneous asthenia in a Campbell's dwarf hamster is described. The animal was found to have hyperextensible skin, glaucoma and lens dislocation. Histopathological examination revealed an irregular, haphazard arrangement of collagen fibres in the dermis. The animal underwent surgical reduction of the skin folds which provided only temporary relief.

Un cas d'asthénie cutanée chez un hamster nain de Campbell est décrit. L'animal présente une peau hyperextensible, un glaucome et une luxation du cristallin. L'examen histopathologique révèle une disposition irrégulière et désordonnée des fibres de collagène dans le derme. L'animal a subi une réduction chirurgicale des plis cutanés qui n'a apporté qu'un soulagement temporaire.

Descreve­se um caso de astenia cutânea em um hamster anão de Campbell. O animal apresentou hiperextensibilidade cutânea, glaucoma e deslocamento de lentes. Ao exame histopatológico, observou­se um arranjo irregular e aleatório das fibras colágenas na derme. O animal foi submetido à redução cirúrgica das dobras cutâneas que resultou em alívio apenas temporário.

Se describe un caso de astenia cutánea en un hámster enano Campbell. Se examinó al animal obsevando piel hiperextensible, glaucoma y luxación del cristalino. El examen histopatológico reveló una orientación aleatoria e irregular de las fibras de colágeno en la dermis. Se utilizó una técnica de reducción quirúrgica de los pliegues de la piel que solo indujo una mejora temporal.

Precision medicine using whole genome sequencing in a cat identifies a novel COL5A1 variant for classical Ehlers-Danlos syndrome.

BACKGROUND: Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable connective tissue disorders occurring in both human and veterinary patients. The genetics of these disorders are poorly described in small animal patients. HYPOTHESIS/OBJECTIVES: Define the clinical manifestations and genetic cause of a suspected form of EDS in a cat. ANIMALS: A 14-week-old male domestic medium hair cat was presented with skin hyperextensibility and fragility. The classic tragic facial expression was observed as well as chronic pruritus and mild hyperesthesia. METHODS: Blood samples and a skin biopsy sample were collected from the affected cat. Clinical examinations, histology, electron microscopy and whole genome sequencing were conducted to characterize the clinical presentation and identify possible pathogenic DNA variants to support a diagnosis. Criteria defining variant pathogenicity were examined including human disease variant databases. RESULTS: Histology showed sparse, disorganized collagen and an increase in cutaneous mast cells. Electron microscopy identified ultrastructural defects commonly seen in collagen type V alpha 1 chain (COL5A1) variants including flower-like collagen fibrils in cross-section. Whole genome sequencing and comparison with 413 cats in the 99 Lives Cat Genome Sequencing Consortium database identified a novel splice acceptor site variant at exon 4 in COL5A1 (c.501-2A>C). CONCLUSIONS AND CLINICAL IMPORTANCE: Our report broadens the current understanding of EDS in veterinary patients and supports the use of precision medicine techniques in clinical veterinary practice. The classification of variants for pathogenicity should be considered in companion animals.

Identification of an ADAMTS2 frameshift variant in a cat family with Ehlers-Danlos syndrome.

We investigated 4 European domestic shorthair kittens with skin lesions consistent with the dermatosparaxis type of the Ehlers-Danlos syndrome, a connective tissue disorder. The kittens were sired by the same tomcat but were born by 3 different mothers. The kittens had easily torn skin resulting in nonhealing skin wounds. Both clinically and histologically, the skin showed thin epidermis in addition to inflammatory changes. Changes in collagen fibers were visible in electron micrographs. The complete genome of an affected kitten was sequenced. A one base pair duplication leading to a frameshift in the candidate gene ADAMTS2 was identified, p.(Ser235fs*3). All 4 affected cats carried the frameshift duplication in a homozygous state. Genotypes at this variant showed perfect cosegregation with the autosomal recessive Ehlers-Danlos syndrome phenotype in the available family. The mutant allele did not occur in 48 unrelated control cats. ADAMTS2 loss-of-function variants cause autosomal recessive forms of Ehlers-Danlos syndrome in humans, mice, dogs, cattle, and sheep. The available evidence from our investigation together with the functional knowledge on ADAMTS2 in other species allows to classify the identified ADAMTS2 variant as pathogenic and most likely causative variant for the observed Ehlers-Danlos syndrome.

Novel Homozygous ADAMTS2 Variants and Associated Disease Phenotypes in Dogs with Dermatosparactic Ehlers-Danlos Syndrome.

Tissue fragility, skin hyperextensibility and joint hypermobility are defining characteristics of Ehlers-Danlos syndrome (EDS). Human EDS is subclassified into fourteen types including dermatosparactic EDS, characterized by extreme skin fragility and caused by biallelic ADAMTS2 mutations. We report two novel, ADAMTS2 variants in DNA from EDS-affected dogs. Separate whole-genome sequences from a Pit Bull Terrier and an Alapaha Blue Blood Bulldog each contained a rare, homozygous variant (11:2280117delC, CanFam3.1), predicted to produce a frameshift in the transcript from the first coding ADAMTS2 exon (c.10delC) and a severely truncated protein product, p.(Pro4ArgfsTer175). The clinical features of these dogs and 4 others with the same homozygous deletion included multifocal wounds, atrophic scars, joint hypermobility, narrowed palpebral fissures, skin hyperextensibility, and joint-associated swellings. Due to severe skin fragility, the owners of all 6 dogs elected euthanasia before the dogs reached 13 weeks of age. Cross sections of collagen fibrils in post-mortem dermal tissues from 2 of these dogs showed hieroglyphic-like figures similar to those from cases of severe dermatosparaxis in other species. The whole-genome sequence from an adult Catahoula Leopard Dog contained a homozygous ADAMTS2 missense mutation, [11:2491238G>A; p.(Arg966His)]. This dog exhibited multifocal wounds, atrophic scars, and joint hypermobility, but has survived for at least 9 years. This report expands the spectrum of clinical features of the canine dermatosparactic subtype of EDS and illustrates the potential utility of subclassifying canine EDS by the identity of gene harboring the causal variant.

Independent COL5A1 Variants in Cats with Ehlers-Danlos Syndrome.

We investigated four cats with similar clinical skin-related signs strongly suggestive of Ehlers-Danlos syndrome (EDS). Cases no. 1 and 4 were unrelated and the remaining two cases, no. 2 and 3, were reportedly siblings. Histopathological changes were characterized by severely altered dermal collagen fibers. Transmission electron microscopy in one case demonstrated abnormalities in the collagen fibril organization and structure. The genomes of the two unrelated affected cats and one of the affected siblings were sequenced and individually compared to 54 feline control genomes. We searched for private protein changing variants in known human EDS candidate genes and identified three independent heterozygous COL5A1 variants. COL5A1 is a well-characterized candidate gene for classical EDS. It encodes the proα1 chain of type V collagen, which is needed for correct collagen fibril formation and the integrity of the skin. The identified variants in COL5A1 are c.112_118+15del or r.spl?, c.3514A>T or p.(Lys1172*), and c.3066del or p.(Gly1023Valfs*50) for cases no. 1, 2&3, and 4, respectively. They presumably all lead to nonsense-mediated mRNA decay, which results in haploinsufficiency of COL5A1 and causes the alterations of the connective tissue. The whole genome sequencing approach used in this study enables a refinement of the diagnosis for the affected cats as classical EDS. It further illustrates the potential of such experiments as a precision medicine approach in animals with inherited diseases.

First reported case of fragile foal syndrome type 1 in the Thoroughbred caused by PLOD1 c.2032G>A.

BACKGROUND: Warmblood Fragile Foal Syndrome Type 1 (WFFS) is an autosomal recessive disorder reported previously only in warmbloods and thought to be caused by a variant in the gene procollagen-lysine,2-oxoglutarate 5-dioxygenase 1 (PLOD1, c.2032G>A, p.Gly678Arg). Given the presentation of this Thoroughbred case, we hypothesised that a similar genetic mechanism caused this phenotype. OBJECTIVES: To describe the pathological and genetic findings on a foal presenting to a veterinary practice in the UK with skin lesions similar to other Ehlers-Danlos Syndromes, including those documented for warmbloods with WFFS. STUDY DESIGN: A single case report describing a genetic investigation. METHODS: A Thoroughbred foal presenting as dystocia was euthanised for multiple skin lesions and developmental abnormalities. DNA extracted from the foal was tested for the PLOD1 variant (c.2032G>A, p.Gly678Arg) using the commercially available assay. To confirm causality and further interrogate potential novel causes of Ehlers-Danlos Syndrome, 1799 functional candidate genes, including PLOD1, were analysed using whole genome sequencing data generated from DNA extracted from the foal's muscle. These data were compared to 34 control samples from at least 11 other breeds. Variants were prioritised for further evaluation based on predicted impact on protein function. RESULTS: Post-mortem evaluation concluded that this foal suffered from a condition of collagen dysplasia. The foal was homozygous for the c.2032G>A PLOD1 variant. Only two other missense variants identified from whole genome sequencing data were also computationally predicted to be deleterious to protein function, (NPHP3 c.1253T>C, p.Leu418Pro, EPDR1 c.154G>C, p.Glu52Gln). Neither of these genes have been linked to similar phenotypes, or Ehlers-Danlos Syndrome in humans or other species and thus further investigation of these variants as the cause of EDS was not warranted. MAIN LIMITATIONS: This study is a single case report in the Thoroughbred with no additional cases from this breed yet identified to replicate this finding. CONCLUSIONS: Given the clinical presentation similar to WFFS, homozygosity for the PLOD1 variant, and absence of another more plausible causal variant from the WGS experiment, we conclude that PLOD1 c.2032G>A is the likely cause of this foal's condition. This is the first documented evidence of fragile foal syndrome caused by the PLOD1 variant in a breed outside of warmbloods, the Thoroughbred. We therefore recommend a change in the name of this disorder to fragile foal syndrome type 1 (FFS) and utilisation of genetic testing in Thoroughbreds to avoid producing affected foals.

Connective Tissue Disorders in Domestic Animals.

Though soft tissue disorders have been recognized and described to some detail in several types of domestic animals and small mammals for some years, they remain uncommon. Because of their low prevalence, not much progress has been made not only in improved diagnosis but also in our understanding of the biochemical basis and pathogenesis of these diseases in animals. Ehlers-Danlos syndrome (EDS) described in dogs already in 1943 and later in cats has only minor impact on the well-being of the dog as its effects on skin of these animals are rather limited. The involved skin is thin and hyperextensible with easily inflicted injuries resulting in hemorrhagic wounds and atrophic scars. Joint laxity and dislocation common in people are less frequently found in dogs. No systemic complications, such as organ rupture or cardiovascular problems which have devastating consequences in people have been described in cats and dogs. The diagnosis is based on clinical presentation and on light or electron microscopic features of disorganized and fragmented collagen fibrils. Several case of bovine and ovine dermatosparaxis analogous to human Ehlers-Danlos syndrome type VIIC were found to be caused by mutations in the procollagen I N-proteinase (pnPI) or ADAMTS2 gene, though mutations in other sites are likely responsible for other types of dermatosparaxis. Cattle suffering from a form of Marfan syndrome (MFS) were described to have aortic dilatation and aneurysm together with ocular abnormalities and skeletal involvement. As in people, mutations at different sites of bovine FBN1 may be responsible for Marfan phenotype. Hereditary equine regional dermal asthenia (HERDA), or hyperelastosis cutis, has been recognized in several horse breeds as affecting primarily skin, and, occasionally, tendons. A mutation in cyclophilin B, a chaperon involved in proper folding of collagens, has been identified in some cases. Warmblood fragile foal syndrome (WFFS) is another Ehlers-Danlos-like disorder in horses, affecting primarily Warmbloods who present with skin fragility and joint hyperextensibility. Degenerative suspensory ligament desmitis (DSLD) affects primarily tendons and ligaments of certain horse breeds. Data from our laboratory showed excessive accumulation of proteoglycans in organs with high content of connective tissues. We have identified increased presence of bone morphogenetic protein 2 (BMP2) in active foci of DSLD and an abnormal form of decorin in proteoglycan deposits. Our most recent data obtained from next generation sequencing showed disturbances in expression of genes for numerous proteoglycans and collagens.

Evaluation of the Filum Terminale in Hereditary Equine Regional Dermal Asthenia.

The objectives of this study were to describe the anatomy, histology, and ultrastructure of the equine filum terminale (FT) and to describe the FT in hereditary equine regional dermal asthenia (HERDA), a model of human Ehlers-Danlos syndromes (EDS). Those humans suffer from tethered cord syndrome (TCS) caused by an abnormally structured FT wherein its attachment at the base of the vertebral column leads to long-term stretch-induced injury to the spinal cord. The pathophysiology of TCS in EDS is poorly understood, and there is a need for an animal model of the condition. Histopathologic and ultrastructural examinations were performed on FT from HERDA (n = 4) and control horses (n = 5) and were compared to FT from human TCS patients with and without EDS. Adipose, fibrous tissue, and neuronal elements were assessed. CD3 and CD20 immunohistochemistry was performed to clarify cell types (HERDA n = 2; control n = 5). Collagen fibrils were assessed in cross-section for fibril diameter and shape, and in longitudinal section for fibril disorganization, swelling, and fragmentation. The equine and human FT were similar, with both containing fibrous tissue, ependyma, neuropil, and nerve twigs. Hypervascularity was observed in both HERDA horses and human EDS-TCS patients and was not observed in equine or human controls. Moderate to severe abnormalities in collagen fibril orientation and architecture were observed in all HERDA horses and were similar to those observed in human EDS-TCS patients.

Identification of Two Independent COL5A1 Variants in Dogs with Ehlers-Danlos Syndrome.

The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable disorders affecting connective tissues. The mutations causing the various forms of EDS in humans are well characterized, but the genetic mutations causing EDS-like clinical pathology in dogs are not known, thus hampering accurate clinical diagnosis. Clinical analysis of two independent cases of skin hyperextensibility and fragility, one with pronounced joint hypermobility was suggestive of EDS. Whole-genome sequencing revealed de novo mutations of COL5A1 in both cases, confirming the diagnosis of the classical form of EDS. The heterozygous COL5A1 p.Gly1013ValfsTer260 mutation characterized in case 1 introduced a premature termination codon and would be expected to result in α1(V) mRNA nonsense-mediated mRNA decay and collagen V haploinsufficiency. While mRNA was not available from this dog, ultrastructural analysis of the dermis demonstrated variability in collagen fibril diameter and the presence of collagen aggregates, termed 'collagen cauliflowers', consistent with COL5A1 mutations underlying classical EDS. In the second case, DNA sequencing demonstrated a p.Gly1571Arg missense variant in the COL5A1 gene. While samples were not available for further analysis, such a glycine substitution would be expected to destabilize the strict molecular structure of the collagen V triple helix and thus affect protein stability and/or integration of the mutant collagen into the collagen V/collagen I heterotypic dermal fibrils. This is the first report of genetic variants in the COL5A1 gene causing the clinical presentation of EDS in dogs. These data provided further evidence of the important role of collagen V in dermal collagen fibrillogenesis. Importantly, from the clinical perspective, we showed the utility of DNA sequencing, combined with the established clinical criteria, in the accurate diagnosis of EDS in dogs.

Evaluation of the Structure of Myodural Bridges in an Equine Model of Ehlers-Danlos Syndromes.

Myodural bridges have been described in various species as connective tissue structures "bridging" small cranio-cervical muscles to the dura. Myodural bridges are thought to stabilize the dural sac during head and neck movements and promote cerebrospinal fluid motion; however, their role in neurological diseases has not yet been established. We report ultrasonographic visualization, necropsy, histopathologic and ultrastructural findings of myodural bridges in horses with hereditary equine regional dermal asthenia (HERDA), an equine model of Ehlers-Danlos syndromes. Five HERDA and 5 control horses were studied. Post-mortem examination and ultrasonographic studies (3 HERDA and 4 controls) demonstrated that the atlanto-occipital and atlanto-axial myodural bridges are dynamic structures "moving" the dura. En block resection of the myodural bridges (4 HERDA and 5 controls) was accomplished and histopathology showed myofiber degeneration in 3 HERDA horses and 1 control. Ultrastructural examination revealed loosely packed collagen fibrils with abnormal orientation in all HERDA horses compared to mild abnormalities in 2 controls. Our study provides necropsy and ultrasonographic evidence of the dynamic aspect of the myodural bridges as dural sac stabilizers. Myodural bridges may be pathologically altered in connective tissue disease as evidenced by the ultrastructural morphology in the HERDA myodural bridge.

A homozygous ADAMTS2 nonsense mutation in a Doberman Pinscher dog with Ehlers Danlos syndrome and extreme skin fragility.

An eight-week old Doberman Pinscher was diagnosed with Ehlers Danlos syndrome based on the dog's hyper-mobile carpal, tarsal and stifle joints and abnormal skin. The skin was loose and hyper-elastic with several wounds and large atrophic scars. The dog was euthanized after a severe degloving injury from minimal trauma. A whole-genome sequence, generated with DNA from the dog's blood, contained a rare, homozygous C-to-T transition at position 2408978 on chromosome 11. This transition is predicted to alter the ADAMTS2 transcript (ADAMTS2:c.769C>T) and encode a nonsense mutation (p.Arg257Ter). Biallelic ADAMTS2 mutations have caused a type of Ehlers Danlos syndrome known as dermatosparaxis in other species.

Warmblood Fragile Foal Syndrome causative single nucleotide polymorphism frequency in Warmblood horses in Brazil.

Warmblood Fragile Foal Syndrome (WFFS) is an autosomal recessive genetic disorder caused by a mutation in the procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) gene, associated with collagen biosynthesis. WFFS causes lesions and malformations of the skin in neonatal foals, and abortion. The objective of this study was to investigate the allelic frequency of the single nucleotide polymorphism (SNP) c.2032G>A in the PLOD1 gene in warmblood samples from Brazil. Of the 374 Warmblood horses tested, 41 animals (11%) were identified as heterozygous for the WFFS SNP and 333 (89%) were homozygous for the wild-type allele (N/N), and therefore, the allele frequency was 5.5%. This study highlights the importance of control measures to prevent an increase in the incidence of WFFS in Warmblood horses worldwide.

A frameshift variant in the COL5A1 gene in a cat with Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a group of heritable connective tissue disorders caused by defective collagen synthesis or incorrect assembly of the collagen triple helical structure. EDS is characterised by joint hypermobility, skin hyperextensibility, abnormal scarring, poor wound healing and tissue friability. Human EDS may be caused by variants in several different genes including COL5A1, which encodes the collagen type V alpha 1 chain. For the present study we investigated a 1.5-year-old, spayed female, domestic shorthair cat with EDS. The affected cat showed multiple recurrent skin tears, hyperextensibility of the skin and joint abnormalities. We obtained whole genome sequencing data from the affected cat and searched for variants in candidate genes known to cause EDS. We detected a heterozygous single base-pair deletion in exon 43 of the COL5A1 gene, namely c.3420delG. The deletion was predicted to result in a frameshift and premature stop codon: p.(Leu1141SerfsTer134). Sanger sequencing confirmed that the variant was present in the affected cat and absent from 103 unaffected cats from different breeds. The variant was also absent from a Burmese cat with EDS. Based on knowledge about the functional impact of COL5A1 variants in other species, COL5A1:c.3420delG represents a compelling candidate causative variant for the observed EDS in the affected cat.

Prevalence study of SNP c.421G>T in the ADAMTS2 gene responsible for dermatosparaxis in white dorper sheep in Brazil / Prevalência do SNP c.421G>T no gene ADAMTS2 responsável pela dermatosparaxia em ovinos white dorper no Brasil

Dermatosparaxis is an autosomal recessive disorder of connective tissue; the disorder is clinically characterized by skin fragility and hyperextensibility. Dermatosparaxis in White Dorper sheep is caused by a single nucleotide polymorphism (SNP) (c.421G>T) in the ADAM metalloproteinase with thrombospondin type 1 motif, 2 (ADAMTS2) gene. The aim of this study was to investigate the prevalence of this SNP in a White Dorper herd in São Paulo state, Brazil. In this study, we collected blood DNA samples from 303 White Dorper sheep and performed polymerase chain reaction to amplify the SNP region. The samples were sequenced to determine the presence of the SNP in the ADAMTS2 gene. The SNP prevalence in the studied population was 15.5%; this finding indicates that more effective control measures should be used to prevent the inheritance of SNP c.421G>T in the ADAMTS2 gene in Brazilian White Dorper herds.

A dermatosparaxia é uma doença autossômica recessiva do tecido conjuntivo, clinicamente caracaterizada pela fragilidade e hiperextensibilidade da pele. A dermatosparaxia em ovinos White Dorper é causada pelo polimorfismo de base única (SNP) c.421G>T no gene ADAM metalopeptidase com trombospondina tipo 1 motif, 2 (ADAMTS2). O objetivo deste estudo foi investigar a prevalência deste SNP em ovinos White Dorper no estado de São Paulo, Brasil. Foram coletadas amostras de sangue de 303 ovinos White Dorper. O DNA foi purificado destas amostras sanguíneas e utilizado em uma reação em cadeia da polimerase (PCR) para amplificação da região do gene contendo SNP c.421G>T. Os produtos das PCR foram sequenciados para determinar o genótipo dos animais. A prevalência do SNP na população estudada foi de 15,5%, estes achados indicam que medidas de controle efetivas devem ser utilizadas para prevenir a disseminação deste SNP no rebanho brasileiro de White Dorper.

Cutaneous asthenia (Ehlers-Danlos-like syndrome) of Burmese cats.

OF CASES: A 6-month-old Burmese kitten developed focal skin lesions following a routine ovariohysterectomy. These were eventually attributed to the patient struggling during catheter placement and induction of anaesthesia. The lesions were caused by fluid extravasation in the subcutis and ischaemic necrosis of the overlying dermis, giving rise to an eschar-like appearance. Such lesions have been seen previously in Burmese cats with cutaneous asthenia and it is thought that they arise due to poor collagenous support for dermal blood vessels. An increased skin extensibility index (>23%) supported a diagnosis of cutaneous asthenia (Ehlers-Danlos-like syndrome), which has been reported as an inherited condition of Burmese cats in Australia, New Zealand and Europe. An additional Burmese cat with cutaneous asthenia is presented in detail, with lifetime follow-up and further salient observations by the owner, a veterinarian. Photographs of three other affected Burmese cats are provided to illustrate the range of presentations encountered with this condition. All five affected cats were presented with eschars, atrophic alopecia and increased skin extensibility, while one cat also had skin ulcers. Routine histopathological examination, including use of special stains such as trichrome, was unhelpful in establishing the diagnosis. CLINICAL REVIEW: The clinical features of this genetic disease of Burmese cats are reviewed, especially in relation to the postulated 'vasculopathy' that gives rise to characteristic skin lesions. Long term management of this condition is discussed briefly.

Increased susceptibility of skin from HERDA (Hereditary Equine Regional Dermal Asthenia)-affected horses to bacterial collagenase degradation: a potential contributing factor to the clinical signs of HERDA.

BACKGROUND: Hereditary equine regional dermal asthenia (HERDA) is a genetic disorder of collagen resulting in fragile, hyper-extensible skin and ulcerative lesions. The predominance of skin lesions have been shown to occur on the dorsum of HERDA-affected horses. While this has been postulated to be due to increased exposure to sunlight of these areas, the precise pathological mechanism which causes this to occur is unclear. HYPOTHESIS/OBJECTIVES: We hypothesized that an increase in collagenase activity, that has been associated with the exposure of dermal fibroblasts to sunlight, will significantly degrade the material properties of skin from HERDA-affected horses when compared to unaffected controls. ANIMALS: Six unaffected and seven HERDA-affected horses, all euthanized for other reasons. METHODS: Full-thickness skin samples from similar locations on each horse were collected and cut into uniform strips and their material properties (tensile modulus) determined by mechanical testing before (n = 12 samples/horse) or after (n = 12 samples/horse) incubation in bacterial collagenase at 37°C for 6 h. The change in modulus following treatment was then compared between HERDA-affected and unaffected horses using a Student's t-test. RESULTS: The modulus of skin from HERDA-affected horses decreased significantly more than that from unaffected horses following collagenase treatment (54 ± 7% versus 30 ± 16%, P = 0.004). CONCLUSIONS AND CLINICAL IMPORTANCE: The significant decrease in the modulus of skin from HERDA-affected horses following collagenase exposure suggests that their altered collagen microarchitecture is more susceptible to enzymatic degradation and may explain the localization of skin lesions in HERDA-affected horses to those areas of the body most exposed to sunlight. These findings appear to support the previously reported benefits of sunlight restriction in HERDA-affected horses.

Dermatosparaxis in two White Doper lambs in Brazil: case report / Dermatosparaxis em dois cordeiros White Dorper no Brasil: relato de caso

Dermatosparaxis is a genetic disease that affects collagen maturation. This disease is characterized by marked impairment of the resistance of collagen fibers that leads to skin fragility, and it may affect several species. This is the first report of dermatosparaxis in sheep in Brazil. Clinically, two White Dorper lambs had multiple skin lacerations in the neck, dorsum and limbs. Transmission microscopy demonstrated irregular collagen fibers arranged in hieroglyphic shape and scanning electron microscopy demonstrated thin collagen fibrils that were not arranged in bundles as observed in the normal dermis. These findings are consistent with the diagnosis of dermatosparaxis.

A dermatosparaxis é uma doença genética que afeta a maturação do colágeno. Essa doença é caracterizada por redução acentuada da resistência das fibras colágenas que leva à fragilidade da pele. Esse é o primeiro relato de dermatosparaxis em ovinos no Brasil. Clinicamente, dois cordeiros da raça White Dorper tiveram múltiplas lacerações na pele do pescoço, dorso e membros. A microscopia de transmissão demonstrou fibras de colágeno irregularares arranjadas em formato de hieroflifo, e a microscopia de varredura demonstrou fibras finas de colágeno não arranjadas em bandas como na derme do animal normal. Esses achados são consistentes com o diagnóstico de dermatosparaxis.