Hereditary motor and sensory neuropathy with treatable extrapyramidal features

Tremor associated with chronic inflammatory demyelinating peripheral neuropathy: treatment with pregabalin

OBJECTIVE

To report a case of a patient with tremor associated with chronic inflammatory demyelinating neuropathy (CIDP) that improved after treatment with pregabalin.

CASE REPORT

A 68-year-old man diagnosed as having CIDP at age 63 years developed postural and kinetic tremor in both hands at age 64 years. Tremor did not improve with propranolol, primidone, phenobarbital, clonazepam, alprazolam, gabapentin, and topiramate, but improved markedly with pregabalin. Tremor worsened after pregabalin withdrawal and improved again after its reintroduction.

CONCLUSIONS

Pregabalin could be useful in the treatment of postural tremor associated with CIDP resistant to other therapies.

Treatment for Charcot-Marie-Tooth disease

BACKGROUND

Charcot-Marie-Tooth disease (CMT) comprises a large variety of different forms of motor and sensory neuropathies. The most frequent are demyelinating forms (CMT1) and axonal forms (CMT2). The molecular basis of several CMT forms has been clarified during the last 15 years. Since muscle wasting and sensory disturbance are the main features of these syndromes, treatments aim to improve motor impairment and sensory disturbances. Specific treatment trials are rare.

OBJECTIVES

The objective was to review systematically all randomised and quasi-randomised studies of any treatment for CMT.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register, MEDLINE (January 1966 to August 2007), EMBASE (January 1980 to August 2007), LILACS (January 1982 to August 2007) for randomised controlled trials of treatment for CMT.

SELECTION CRITERIA

We included randomised and quasi-randomised trials of any treatment for people with CMT. Where a study aimed to evaluate the treatment of general neuromuscular symptoms of people with peripheral neuropathy including CMT, we included the study if we were able to identify the effect of treatment in the CMT group. Observational studies and case reports on the treatment of people with CMT were not included.

DATA COLLECTION AND ANALYSIS

Two review authors (PY and TBB) extracted the data, assessed study quality and performed data extraction independently.

MAIN RESULTS

Only one trial with only eight participants met all the inclusion criteria and provided the primary outcome measure for this review. In this trial, four participants treated with neurotrophin-3 had more improvement after six months on the Neuropathy Impairment Score, mean difference -9.50 (95% CI -13.77 to -5.23), than those four treated with placebo. Small trials of exercise training, creatine monohydrate, orthoses and purified bovine brain ganglioside injections (Cronassial) showed no significant benefit in people with genetically undefined CMT1 or CMT2.

AUTHORS' CONCLUSIONS

Small trials of exercise, creatine, purified brain gangliosides, and orthoses have been performed. None showed significant benefit. A very small trial of neurotrophin-3 showed possible minor benefit which needs to be replicated in a larger trial. None of the two trials were large enough to detect moderate benefit or harm. Larger RCTs are needed for any form of pharmacological intervention as well as as for any form of physical intervention. Outcome measures should include a validated composite scale such as the Charcot-Marie-Tooth neuropathy scale.

Charcot-Marie-Tooth disease (CMT): distinctive phenotypic and genotypic features in CMT type 2

Charcot-Marie-Tooth disease (CMT), or hereditary motor and sensory neuropathy (HMSN), includes two main subtypes of CMT1/HMSN I (demyelinating), and CMT2/HMSN II (axonal). Further heterogeneity has been demonstrated by genetic molecular studies, with at least four responsible genes for CMT1. As for CMT2, a mutation in the neurofilament-light (NF-L) gene has been identified in a single family, and other CMT2 loci have been mapped. We propose a clinical classification of the CMT2 phenotypes, and review the features of the identified CMT2 genotypes. The following main subtypes of CMT2 are considered in the phenotype classification: classical CMT2, the variants of CMT2 showing atypical features that may represent either variance in the classical CMT2 phenotype or separate entities; CMT2 plus, i.e. complex forms with involvement of additional neural structures. The recognized CMT2 genotypes include: CMT2A (mapped to chromosome 1p35-36); CMT2B (3q13-22); CMT2C (with vocal cord paresis); CMT2D (7p14); CMT2E, related to a mutation in the NF-L gene on chromosome 8p21; proximal CMT2, or HMSN P (3q13.1); CMT2 with MPZ mutations; autosomal recessive CMT2 (1q21.2-q21.3); agenesis of the corpus callosum with sensorimotor neuronopathy (15q13-q15); CMT2 X-linked with deafness and mental retardation (Xq24-q26). The identified genotypes may correspond to previously described clinical subtypes of CMT2. In particular, classical CMT2 presents in association with NF-L gene mutation, in the only CMT2 family with known gene mutation, and in CMT2A patients. However, the features of classical CMT2 have been paradoxically reported also in families with MPZ mutation, and conversely several CMT2 families are not linked to the known CMT2 loci. Further cloning of the CMT2 genes will ultimately shed light on the pathogenic mechanism(s) implicated in the process of axonal degeneration, shared by the different CMT2 genotypes.

Dopa-responsive parkinsonism phenotype of Machado-Joseph disease: confirmation of 14q CAG expansion

The subtype IV of Machado-Joseph disease (MJD), characterized by parkinsonism variably combined with ataxia, distal atrophy, and sensory loss, has been all but ignored in recent reports of MJD, including those describing the molecular biologic substrate of the disease. We have demonstrated expansion of the CAG trinucleotide repeat of the MJD1 gene located on chromosome 14q32.1 in 2 patients of Azorean descent who presented with levodopa-responsive atypical parkinsonism. Previous publications have documented the presence of this expanded repeat in the other more common MJD phenotypes (I-III). To our knowledge, this is the first molecular biologic confirmation of the presence of the MJD1 gene in the subtype IV phenotype. Patients presenting with parkinsonism and peripheral neuropathy should be screened for this genetic defect.

The role of the basal ganglia in nociception and pain

The involvement of the basal ganglia in motor functions has been well studied. Recent neurophysiological, clinical and behavioral experiments indicate that the basal ganglia also process non-noxious and noxious somatosensory information. However, the functional significance of somatosensory information processing within the basal ganglia is not well understood. This review explores the role of the striatum, globus pallidus and substantia nigra in nociceptive sensorimotor integration and suggests several roles of these basal ganglia structures in nociception and pain. Electrophysiological experiments have detailed the non-nociceptive and nociceptive response properties of basal ganglia neurons. Most studies agree that some neurons within the basal ganglia encode stimulus intensity. However, these neurons do not appear to encode stimulus location since the receptive fields of these cells are large. Many basal ganglia neurons responsive to somatosensory stimulation are activated exclusively or differentially by noxious stimulation. Indirect techniques used to measure neuronal activity (i.e., positron emission tomography and 2-deoxyglucose methods) also indicate that the basal ganglia are activated differentially by noxious stimulation. Neuroanatomical experiments suggest several pathways by which nociceptive information may reach the basal ganglia. Neuroanatomical studies have also indicated that the basal ganglia are rich in many different neuroactive chemicals that may be involved in the modulation of nociceptive information. Microinjection of opiates, dopamine and gamma-aminobutyric acid (GABA) into the basal ganglia have varied effects on pain behavior. Administration of these neurochemicals into the basal ganglia affects supraspinal pain behaviors more consistently than spinal reflexive behaviors. The reduction of pain behavior following electrical stimulation of the substantia nigra and caudate nucleus provides additional evidence for a role of the basal ganglia in pain modulation. Some patients with basal ganglia disease (e.g., Parkinson's disease, Huntington's disease) have alterations in pain sensation in addition to motor abnormalities. Frequently, these patients have intermittent pain that is difficult to localize. Collectively, these data suggest that the basal ganglia may be involved in the (1) sensory-discriminative dimension of pain, (2) affective dimension of pain, (3) cognitive dimension of pain, (4) modulation of nociceptive information and (5) sensory gating of nociceptive information to higher motor areas. Further experiments that correlate neuronal discharge activity with stimulus intensity and escape behavior in operantly conditioned animals are necessary to fully understand how the basal ganglia are involved in nociceptive sensorimotor integration.

Peroneal muscular atrophy with parkinsonism, ptosis, and congenital strabismus

Peroneal muscular atrophy (PMA) may be occasionally associated with other neurodegenerative features including parkinsonism. We report the association of PMA of neuronal type with parkinsonism, ptosis and congenital strabismus in a 62-year-old Sicilian woman. The complete syndrome was present only in the proband, but variously combined features were present in ten other family members over four generations, with likely autosomal dominant inheritance. Although a similar syndrome of PMA, ptosis, parkinsonism and dementia was already reported, this family showed a previously undescribed combination of features in view of the presence of congenital strabismus.

Hereditary motor-sensory neuropathy and movement disorders

To explore the relationship between hereditary motor and sensory neuropathy (HMSN) and movement disorders, we examined 7 patients with HMSN referred to our Movement Disorders Clinic and surveyed members of the Charcot-Marie-Tooth association. The following movement disorders were observed in the index patients: postural tremor in 6, rest tremor in 3, and Parkinsonism and dystonia in 2. Tremor, present in 40% of the 201 patients who responded to the survey, was first noted at a mean age of 36 years, and mostly involved the hands. Family history of tremor was more frequent in the tremor group (P < 0.005), which also had a significantly worse writing score than the nontremor group (P < 0.001). The overlap in clinical features between HMSN-associated tremor and essential tremor (ET), the high frequency of family history of tremor, and the lack of a relationship between the severity of tremor and of peripheral neuropathy suggest that the tremor in HMSN is pathogenically related to ET.