Acute vincristine neurotoxicity in the presence of hereditary motor and sensory neuropathy type I.

Acute vincristine neurotoxicity leading to a severe motor and sensory neuropathy has been noted in patients with hereditary motor and sensory neuropathy type I (HMSN-I). The case of a 2-year-old boy with acute lymphocytic leukemia and HMSN-I is reported, and additional cases from the literature are reviewed. Severe vincristine neurotoxicity in patients with HMSN-I may be secondary to impairment of both slow and- fast axonal transport. Vincristine should be used with caution in patients with a family history of polyneuropathy.