Axonal motor and sensory neuropathy in myotonic dystrophy

Abstract

We report the neurophysiological findings from 24 subjects with myotonic dystrophy of Steinert and the histological findings in two of them. The conduction data is compared with that of a group of subjects with Landouzy‐Déjérine muscular dystrophy. In 46% of cases, the electrophysiological data revealed slight and generalized axonal neuropathy. Histological results of sural nerve confirmed axonal damage of sensory fibres. The neuropathy was not correlated with age of patients, duration or onset of the disease, nor with the state of the deep reflexes; it did not show signs of progressing and is probably one of the multisystemic manifestations of gene pleiotropism.

Abnormalities of nerve conduction studies in myotonic dystrophy type 1: Primary involvement of nerves or incidental coexistence?

“…The common feature in these reports is that, in DM1 patients, PN is an axonal neuropathy that tends to progress in a stepwise fashion irrespective of the clinical severity of myopathy. 21 Hence, despite the denial of PN in patients with DM1 by other authors, [5][6][7][8][9] it is generally accepted that PN can occur with DM1. At the same time, controversy continues about whether PN in DM1 is primary or secondary to other causes such as diabetes or drugs.…”

“…3,4,12 Some authors have insisted that PN is not uncommon and exists in 20%-30% of patients with DM1. [18][19][20][21] This thesis is supported by electrophysiological, 18,21,22 pathological, 20 and clinical findings. The common feature in these reports is that, in DM1 patients, PN is an axonal neuropathy that tends to progress in a stepwise fashion irrespective of the clinical severity of myopathy.…”

Peripheral nerve involvement in myotonic dystrophy type 2 – similar or different than in myotonic dystrophy type 1?

“…The issue of peripheral nerve involvement in DM1 is still a matter of debate. Although patients seldom complain of sensory symptoms, some authors described peripheral neuropathy [13][14][15][16][17][18] or abnormal results of peripheral nerve conduction studies [19][20][21][22] in patients with DM1. Other reports, however, indicate no primary peripheral nervous system involvement in DM1 [23][24][25][26].…”

Combination of myotonic dystrophy and hereditary motor and sensory neuropathy

“…A linkage to the HMSN genes could not be shown. An association with diabetes mellitus was also largely excluded [4,[6][7][8]. In contrast, in the Index case described in this paper, the reason for polyneuropathy was firmly established by the presence of a CMT1 mutation, in addition to her DM1 mutation.…”

“…In the literature there are controversial results for the involvement of the peripheral nervous system in DM. Axonopathy was reported, involving both the motor and the sensory nerves, rather than demyelination in electrophysiological investigation of DM patients [4][5][6][7][8][9]. However, morphological and morphometric analyses of DM1 transgenic mice, carrying 300 CTG repeats, did not reveal axonal degeneration, sensory and motor neuropathy and a significant demyelination [10].…”