Generalised vertebral abnormalities in a Rhodesian ridgeback with a lysosomal storage disease

A 3-year, 11-month male neutered Rhodesian ridgeback presented for evaluation of cervical hyperaesthesia, generalised ataxia and right thoracic limb lameness. Neurological examination was suggestive of a lesion affecting the C1–C5 spinal cord segments. MRI of the neck identified an irregularly shaped and shortened vertebral body of C6, a mild subluxation between C5 and C6, multiple hypertrophic and abnormally shaped articular processes, and multiple dorsal lamina abnormalities. CT confirmed these findings and revealed additionally multiple visible fracture lines and identified the axial and appendicular skeleton to be characterised by abnormally hypoattenuating cancellous bone and a thin cortex. The dog was euthanased and a postmortem examination confirmed generalised osteoporosis, vertebral malformations and identified distended and swollen neurons in the cerebrum, hippocampus, cerebellum and brainstem, containing intracytoplasmic, granular, PAS-positive inclusions. These findings were considered consistent with a lysosomal storage disease, with a presumptive diagnosis of mucopolysacharidosis being most likely.