Adult-onset Krabbe disease presenting with an isolated form of peripheral neuropathy.

Introduction: Adult-onset Krabbe disease is clinically rare and usually affects the pyramidal tracts in the central nervous system. Patients develop a spastic gait, and peripheral neuropathy sometimes occurs simultaneously.

Methods: A 55-year-old woman with consanguineous parents developed slowly progressive, asymmetric muscle weakness and atrophy in her forearms, while her ability to walk remained unaffected without pyramidal tract signs after onset at age 51 years.

Results: Nerve conduction studies demonstrated an asymmetric demyelinating-type peripheral neuropathy, and sural nerve biopsy documented reduced myelinated nerve fiber density with uniformly thin myelin sheaths, suggesting hypomyelination. Brain MRI demonstrated minor white-matter injury along the optic radiations, which was associated with asymptomatic, mild, prolonged latency on visual evoked potentials. Laboratory analysis documented low enzyme activity of galactocerebrosidase (GALC) and a known mutation of the GALC gene.

Conclusion: Isolated peripheral neuropathy occurs very rarely in adult-onset Krabbe disease. Muscle Nerve 54: 152-157, 2016.