Peer-reviewed veterinary case report
Arabian horse with neck malformations but no HOXD3 gene mutation
By Vanderbiest, Lola et al.·Published in Journal of equine veterinary science·2026·Equitom Namur Equine Clinic·View original on PubMed →
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Original publication title: Evidence of occipitoatlantoaxial malformations independent of the HOXD3 mutation in an Arabian horse.
- Species:
- horse
Plain-English summary
A 3-year-old Arabian gelding was brought in with severe neck stiffness and difficulty coordinating his movements, known as proprioceptive ataxia. X-rays showed serious malformations in the bones of his neck, but testing for a known genetic mutation linked to this condition came back negative. Unfortunately, due to his poor prognosis and significant mobility issues, the decision was made to euthanize him. This case illustrates that even without the known genetic marker, horses can still suffer from serious neck deformities.
People also search for: Arabian horse neck stiffness · proprioceptive ataxia in horses · horse cranio-cervical malformations
Abstract
Occipitoatlantoaxial malformations (OAAM) are developmental disorders occurring at the occiput, atlas and axis. OAAM type 1 is a familial disorder affecting Arabian horses. Currently, a single genetic mutation in the HOXD3 gene region can be tested to confirm the diagnosis. This case describes a 3-year-old Arabian gelding affected with OAAM. Clinical examination revealed a proximal cervical deformation on the right side and severe stiffness of the neck in the sagittal plane without associated pain. Neurological examination demonstrated a generalized proprioceptive ataxia. Radiographs revealed severe cranio-cervical vertebral malformations. This horse tested negative for the genetic mutation in the HOXD3 gene. Considering the poor prognosis and a generalized grade 3/5 proprioceptive ataxia, euthanasia was elected. This case highlights the phenotypic variability of familial OAAM type 1, showing that this kind of cranial cervical vertebral malformation may be diagnosed or detected in adult horses. Further investigations are needed to better understand the genetic heterogeneity of OAAM.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41980677/