Características Fenotípicas Do Nanismo Em Pôneis Neonatos: Relato De Casos.

Abstract

RESUMOForam atendidos no Hospital Veterinário, três neonatos com características fenotípicas de nanismo, sendo dois MiniHorses e um Pônei Brasileiro. Os animais apresentavam desproporcionalidade craniana, defeito de oclusão dentária e alterações osteo-musculares compatíveis com a anormalidade, como a deformação dos ossos metatarsianos e membros desproporcionalmente curtos. Ao exame radiográfico foram identificadas alterações fisárias de côndilos femorais e em epífise proximal dos terceiros ossos metatarsianos. Devido à elevada possibilidade de futuras complicações e perda da qualidade de vida, os animais foram submetidos à eutanásia. Ressalta-se a importância da divulgação e reconhecimento das alterações fenotípicas relacionadas como o nanismo em equinos, possibilitando que o diagnóstico possa direcionar os cruzamentos para a não transmissão desta anormalidade como herança genética. PALAVRAS-CHAVE:Deformidade de membros. Mini-horse. Osteocondrodisplasia. Pônei. Prognatismo. SUMMARYThree newborn Mini-Horses and one Brazilian Pony horses were presented to the Veterinary Hospital with phenotypic appearance of dwarfism. They had relatively larger head conformation, occlusive dental defect and musculoskeletal changes such as abnormal short limbs and deformation on the third metatarsal bone. The radiographic examination showed abnormal growth plates on femoral condyle and proximal thirds metatarsal bones. Due to the high possibility of future complications and quality of life loss, the animals were euthanized. We emphasize the importance of recognition of phenotypic changes related to dwarfism in horses, enabling the phenotypic diagnosis can direct crossings for nontransmission of this abnormality as genetic inheritance.

Evaluation of a new variant in the aggrecan gene potentially associated with chondrodysplastic dwarfism in Miniature horses

“…The clinical signs observed in the Miniature horses with dwarfism described here were similar to those previously reported 2 , 5 , 11 , 12 . As ACAN - D1 was not observed in the dwarf Miniature horses of the present study, the clinical signs that this variant can cause (cleft palate with protruding tongue, large abdominal hernia and embryonic or late term loss) 2 were not reported in the affected animals of the present study.…”

“…This animal presented with respiratory distress, tachypnoea, inspiratory honking noises and dysphagia. The other dwarfs had no clinical signs of tracheal collapse, but airway endoscopy revealed mild tracheal collapse in eight of ten dwarf Miniature horses (animals [5][6][7][8][9][10][11][12][13][14]. Moreover, other abnormalities were observed during airway endoscopy examination, such as dorsal displacement of the soft palate (5/10) and thickening of both arytenoid cartilages (4/10).…”

“…Most D1 genotypes ( D1 / D1 , D1 / D2 , D1 / D3* and D1 / D4 ) cause foetal death 2 , whereas the other genotypes ( D2 / D2 , D2 / D3* , D2 / D4 , D3* / D3* , D3* / D4 and D4 / D4 ) are involved in the birth of dwarf foals 2 , 5 , 11 . Clinical diagnosis of chondrodysplastic dwarfism in Miniature horses has already been described in Brazil 12 , and the D4 / D4 genotype was recently characterized in the same country 11 . However, it is still not possible to associate all dwarf Miniature horses with the previously described ACAN variants 2 .…”