Evidence of small-fiber neuropathy in neurofibromatosis type 1.

INTRODUCTION

Large-fiber neuropathy is rare in neurofibromatosis type 1, but small-fiber neuropathy has not been studied.

METHODS

Patients with neurofibromatosis type 1 underwent nerve conduction studies for large-fiber assessment. Small-fiber tests included quantitative thermal thresholds, laser Doppler flare imaging, intraepidermal nerve fiber density, and corneal nerve fiber length.

RESULTS

Of the 52 patients enrolled, 31 (60%) were female and the mean age was 33.0 ± 12.3 years. Four (8%) patients had abnormal nerve conduction studies. Small-fiber tests were frequently abnormal: thermal thresholds in 7 (13%); laser Doppler flare imaging in 10 (19%); intraepidermal nerve fiber density in 11 (22%); and corneal nerve fiber length in 27 (52%). The mean corneal nerve fiber length was below normative level (10.1 ± 2.7 mm/mm3 ).

DISCUSSION: Small-fiber neuropathy may be common in neurofibromatosis type 1, and should be investigated in symptomatic patients.