Prospective study of peripheral neuropathy in Machado–Joseph disease

Abstract

Peripheral neuropathy (PN) has long been recognized in Machado-Joseph disease (MJD), but its natural history is an unsettled issue. Therefore, we prospectively assessed 40 with MJD for 13 months with nerve conduction (NC) studies and the revised total neuropathy score (TNSr) to study the progression of PN. There was no significant change in the TNSr score over the follow-up period. In contrast, the average sural sensory nerve action potential (SNAP) amplitude decreased significantly over the same interval from a mean of 13.2 muV to 9.8 muV (P < 0.001). There was an inverse correlation between the change in the sural SNAP amplitude and the length of the CAG triplet repeat expansion (r = 0.574, P < 0.001). The reduction in the mean sural SNAP amplitude also correlated with progression of ataxia. This indicates that PN progresses faster in individuals with larger (CAG)(n) expansions, and nerve conduction studies may be useful to study disease progression in MJD.

Pattern of Peripheral Nerve Involvement in Machado-Joseph Disease: Neuronopathy or Distal Axonopathy? A Clinical and Neurophysiological Evaluation

“…We found no correlation between CAG repeat length and neuropathy or TNSc scores, which is in line with previous data [11,14,15]. Conversely, there was a significant positive correlation between the presence of neuropathy and the age of the patients.…”

“…Our neurophysiological studies showed that neuronopathy was present in 81.8% of MJD patients with neuropathy, which is in line with that reported by França et al [15] and higher than other data [14]. Considering that neuronopathy is the main pattern of nerve involvement in MJD patients, it suggests that damage to neuronal cell bodies is a major factor leading to peripheral neuropathy in these patients rather than axonal damage that would lead to length-dependent distal neuropathy [3,4,14,19].…”

“…Recent data has demonstrated that peripheral nervous system involvement in MJD may be a typical length-dependent axonopathy or a primary neuronopathy [14,15]. However, the most common pattern of peripheral nerve involvement in MJD patients is not yet clear.…”

Is Neuropathy Involved with Restless Legs Syndrome in Machado-Joseph Disease?

“…Peripheral neuropathy has long been recognized in SCA3/MJD patients [15]. In our study, among 26 patients studied, 9 (34%) had neuropathy.…”

Administration of Vincristine in a Patient with Machado-Joseph Disease

“…Extrapyramidal signs comprise dystonic movements, chorea and parkinsonian features. Later, evidence of progressive symptomatic peripheral polyneuropathy with impairment in sensory nerve action potentials can occur [2]. Late in the disease course, patients are confined to a wheelchair, and later become bedridden.…”