Suspected hereditary sensory and autonomic neuropathies: clinical signs and electrodiagnostic findings in eleven dogs

Background: There is limited information available regarding the electrodiagnostic studies (EDX) features of hereditary sensory and autonomic neuropathies (HSANs) in dogs. Hypothesis/objectives: To retrospectively describe the clinical and electrodiagnostic findings of dogs with suspected HSAN and to assess whether comprehensive EDX can assist in disease classification and prognostication. Animals: Eleven client-owned dogs with early-onset distal sensory loss. Methods: Multicentric retrospective observational study (2008-2025). Inclusion criteria were distal sensory loss before 1 year of age, acral mutilations or analgesia of the toes, and complete EDX. Results of sensory nerve conduction studies (SNCS) and cord dorsum potential (CDP) were compared with normal values and with control dogs using an exact permutation test. Results: Two electroclinical patterns emerged. Pattern 1 included dogs with acral mutilation, preserved gait, and recordable but significantly reduced sensory nerve action potential (SNAP) amplitudes, sensory nerve conduction velocity (NCV), and CDP amplitudes (P < .05). Pattern 2 included dogs with tetraparesis and proprioceptive deficits; SNAPs and CDPs were absent in most nerves tested, and motor nerve conduction studies (MNCS) showed reduced compound muscle action potential amplitudes or reduced motor NCV, or both. Dogs in pattern 2 were euthanized within 12 months, whereas 5 of the 6 pattern 1 dogs showed stable or slowly progressive disease. Conclusions and clinical importance: Comprehensive EDX, including SNCS and CDP, identifies sensory and possible concomitant motor dysfunction in dogs with suspected HSAN and differentiates distinct electroclinical patterns associated with prognosis.