A 25 year old presents with tunnel vision and gait instability. She's had neurologic problems all her life; at age 5, she was diagnosed with a sensory motor neuropathy - hypesthesia, hypalgesia, loss of proprioception, and absent tendon reflexes. Since then she's had generalized muscle weakness with distal muscle atrophy. As a result, she has ataxia. A peripheral nerve biopsy revealed loss of large myelinated fibers. She says a grandmother of hers had retinitis pigmentosa. Review of systems is positive for steatorrhea. A blood smear is shown above.
Challenge: This is a tough one, but the smear suggests what disease?
Image is in the public domain.