June 11, 2015: Distal Hereditary Neuropathies
June 11, 2015
Distal Hereditary Neuropathies
The distal hereditary neuropathies (dHMN) are a heterogeneous group of disorders that can mimic the axonal forms of the hereditary motor and sensory neuropathies or the distal myopathies. However, dHMN are characterized by a progressive atrophy and paresis of the lower, greater than upper distal extremities, classically the gastrocnemius, peroneal, and intrinsic hand muscles; at times, with mild sensory symptoms1. Nerve conduction studies, though, are often normal and EMG demonstrates chronic distal denervation. This group of disorders was organized in 1993 into seven categories distinguished by age of onset and pattern of weakness. The genetics of the dHMN are varied and panels are available to sequence the most common genes implicated in this group of disorders. Whole exome sequencing can be helpful in the identification of novel genes in the affected families2.
- Rossor AM, Kalmar B, Greensmith L, Reilly MM. The distal hereditary motor neuropathies. Journal of Neurology, Neurosurgery & Psychiatry 2012; 83: 6-14.
- Gess B, Auer-Grumbach M, Schirmacher A, et al. HSJ1-related hereditary neuropathies: novel mutations and extended clinical spectrum. Neurology 2014; 83: 1726-1732.
Submitted by Adam Numis, MD, Department of Neurology, University of California, Los Angeles.
Disclosures: Dr. Numis is a member of the Residents & Fellows Section of Neurology.