Validation of the Italian version of the Pediatric CMT Quality of Life Outcome Measure

BACKGROUND AND AIMS

The pediatric Charcot-Marie-Tooth (CMT) specific Quality of Life (QOL) outcome measure (pCMT-QOL) is a recently developed and validated patient reported measure of health QOL for children with CMT. The aim of this study was to provide and validate an Italian version of the pCMT-QOL.

METHODS

The original English version was translated and adapted into Italian using standard procedures. pCMT-QOL was administered to patients genetically diagnosed with CMT, aged 8 to 18 years. A retest was given 2 weeks later to assess reliability in all patients.

RESULTS

A total of 22 patients (median age 14 years, DS 2.5; M:F 1:1) affected with CMT (19 CMT1A, 2 CMT2A, 1 CMT2K) were assessed as part of their clinical visit. The Italian-pCMT-QOL demonstrate a high test-retest reliability. None of the patients experienced difficulty in completing the questionnaire, no further corrections were needed after administration in patients.

INTERPRETATION

The Italian-pCMT-QOL is a reliable, culturally adapted, and comparable version of the original English pCMT-QOL.

Recommendations for pre-symptomatic genetic testing for hereditary transthyretin amyloidosis in the era of effective therapy: a multicenter Italian consensus

Hereditary transthyretin amyloidosis (ATTRv, v for variant) is a late-onset, autosomal dominant disease caused by progressive extracellular deposition of transthyretin amyloid fibrils, leading to organ damage and death. For other late-onset fatal diseases, as Huntington’s disease, protocols for pre-symptomatic genetic testing (PST) are available since decades. For ATTRv, limited experience has been reported to date, mostly gathered before the availability of approved therapies. We aimed at developing recommendations for a safe and feasible PST protocol in ATTRv in the era of emerging treatments, taking also into account Italian patients’ characteristics and healthcare system rules. After an initial survey on ongoing approaches to PST for ATTRv in Italy, two roundtable meetings were attended by 24 experts from 16 Italian centers involved in the diagnosis and care of this disease. Minimal requirements for PST offer and potential critical issues were highlighted. By November 2019, 457 families affected by ATTRv with 209 molecularly confirmed pre-symptomatic carriers were counted. The median age at PST was 41.3 years of age, regardless of the specific mutation. Half of the Italian centers had a multidisciplinary team, including a neurologist, an internist, a cardiologist, a medical geneticist and a psychologist, although in most cases not all the specialists were available in the same center. A variable number of visits was performed at each site. Experts agreed that PST should be offered only in the context of genetic counselling to at risk individuals aged 18 or older. Advertised commercial options for DNA testing should be avoided. The protocol should consist of several steps, including a preliminary clinical examination, a pre-test information session, an interval time, the genetic test and a post-test session with the disclosure of the test results, in the context of an experienced multidisciplinary team. Recommendations for best timing were also defined. Protocols for PST in the context of ATTRv can be refined to offer at risk individuals the best chance for early diagnosis and timely treatment start, while respecting autonomous decisions and promoting safe psychological adjustment to the genetic result.

Treadmill training in patients affected by Charcot-Marie-Tooth neuropathy: results of a multicenter, prospective, randomized, single-blind, controlled study

Background and purpose

Muscle‐strengthening, stretching or proprioceptive treatments may slow symptom progression in Charcot—Marie–Tooth (CMT) neuropathy. The aim of the study was to evaluate safety and efficacy of treadmill training in CMT1A.

Methods

We planned a multicenter, prospective, randomized, single‐blind, controlled study. We recruited 53 outpatients affected by CMT1A and randomized them into two treatment groups: one underwent stretching and proprioceptive exercise, whereas the other was additionally treated with treadmill training (TreSPE). Primary outcome measures (OMs) were the walking evaluations and secondary OM was the balance assessment. All participants were assessed at baseline and after 3 and 6 months of treatment.

Results

Most patients showed an improvement in at least one OM after 3 months [42/47 (89.4%)] and 6 months [38/40 (95%)] of treatment. No adverse events were reported in either group.

Conclusions

The most important finding was that both stretching and proprioceptive exercise and treadmill training had an objective benefit on patients affected by CMT disease, without causing overwork weakness. We had a low rate of drop out and did not find deterioration in motor performance. Our results also confirm that applying evidence‐based medicine methods to rehabilitative research is the correct way to test the efficacy of a treatment.

No effect of AR polyG polymorphism on spinal and bulbar muscular atrophy phenotype

BACKGROUND AND PURPOSE

Disease severity varies considerably among patients with Spinal and Bulbar Muscular Atrophy (SBMA). Our aim was to investigate the role of androgen receptor (AR) polymorphic repeats in SBMA phenotype.

METHODS

We analyzed the length of AR polyQ and polyG tracts in 159 SBMA patients.

RESULTS

No relationship between polyG size or polyG/polyQ haplotypes and clinical phenotype was found. An independent negative correlation between polyQ-length and onset of weakness was confirmed (P < 0.001).

CONCLUSIONS

The negative results of our study prompt to continue the search for potential disease modifiers in SBMA outside the AR gene.

Altered TDP-43-dependent splicing in HSPB8-related distal hereditary motor neuropathy and myofibrillar myopathy

BACKGROUND AND PURPOSE

Mutations in the small heat-shock protein 22 gene (HSPB8) have been associated with Charcot-Marie-Tooth disease type 2L, distal hereditary motor neuropathy (dHMN) type IIa and, more recently, distal myopathy/myofibrillar myopathy (MFM) with protein aggregates and TDP-43 inclusions. The aim was to report a novel family with HSPB8^K141E -related dHMN/MFM and to investigate, in a patient muscle biopsy, whether the presence of protein aggregates was paralleled by altered TDP-43 function.

METHODS

We reviewed clinical and genetic data. We assessed TDP-43 expression by qPCR and alternative splicing of four previously validated direct TDP-43 target exons in four genes by reverse transcriptase-polymerase chain reaction.

RESULTS

The triplets and their mother presented in the second to third decade of life with progressive weakness affecting distal and proximal lower limb and truncal muscles. Nerve conduction study showed a motor axonal neuropathy. The clinical features, moderately raised creatin kinase levels, selective pattern of muscle involvement on magnetic resonance imaging and pathological changes on muscle biopsy, including the presence of protein aggregates, supported the diagnosis of a contemporary primary muscle involvement. In affected muscle tissue we observed a consistent alteration of TDP-43-dependent splicing in three out of four TDP-43-target transcripts (POLDIP3, FNIP1 and BRD8), as well as a significant decrease of TDP-43 mRNA levels.

CONCLUSIONS

Our study confirmed the role of mutated HSPB8 as a cause of a combined neuromuscular disorder encompassing dHMN and MFM with protein aggregates. We identified impaired RNA metabolism, secondary to TDP-43 loss of function, as a possible pathological mechanism of HSPB8^K141E toxicity, leading to muscle and nerve degeneration.

Nerve conduction velocity in CMT1A: what else can we tell?

BACKGROUND AND PURPOSE

Charcot-Marie-Tooth disease (CMT) type 1A is characterized by uniformly reduced nerve conduction velocity (NCV) that is fully penetrant since the first years of life, remains fairly stable through the life and does not correlate with disability whereas compound muscular action potential (CMAP) amplitude does. The aim of the present study was to analyze the large amount of electrophysiological data collected in the ascorbic acid trial in Italy and the UK (CMT-TRIAAL/CMT-TRAUK) and to use these data to gain insights into the pathophysiology of NCV in CMT1A.

METHODS

Baseline electrophysiological data from 271 patients were analysed. Electrophysiological recordings were taken from the motor ulnar, median and peroneal nerves and the sensory ulnar nerve. Distal motor latency (DML), motor (MNCV) and sensory (SNCV) nerve conduction velocity, and amplitudes of CMAPs and sensory action potentials were assessed. Electrophysiological findings were correlated with age of patients at examination and the Charcot-Marie-Tooth Examination Score (CMTES).

RESULTS

NCV was markedly and uniformly reduced. CMAP amplitudes were overall reduced but more severely in lower limbs. DML decreased and MNCV and SNCV increased with age of the patients, whereas CMAP amplitudes worsened with age and also correlated with CMTES.

CONCLUSIONS

This is the largest sample of electrophysiological data obtained so far from CMT1A patients. Axonal degeneration as assessed by means of CMAP amplitude reflected clinical impairment and was consistent with a slowly progressive length-dependent neuropathy. All patients typically had markedly slowed NCV that did, however, slightly increase with age of the patients. The improvement of NCV might depend on myelin thickness remodelling that occurs during the adult life of CMT1A patients.

Laryngeal and phrenic nerve involvement in a patient with hereditary neuropathy with liability to pressure palsies (HNPP)

Lower cranial and phrenic nerve involvement is exceptional in hereditary neuropathy with liability to pressure palsies (HNPP). Here we report the occurrence of reversible laryngeal and phrenic nerve involvement in a patient with HNPP. The patient recalled several episodes of reversible weakness and numbness of his feet and hands since the age of 30 years. His medical history was uneventful, apart from chronic obstructive pulmonary disease (COPD). At age 44, following severe weight loss, he presented with progressive dysphonia and hoarseness. EMG of cricoarytenoid and thyroarytenoid muscles and laryngeal fibroscopy confirmed vocal cord paralysis. These speech disturbances gradually regressed. Two years later, he reported rapidly worsening dyspnea. Electroneurography showed increased distal latency of the right phrenic nerve and diaphragm ultrasonography documented reduced right hemi-diaphragm excursion. Six months later and after optimization of CODP treatment, his respiratory function had improved and both phrenic nerve conduction and diaphragm excursion were completely restored. We hypothesize that chronic cough and nerve stretching in the context of CODP, together with severe weight loss, may have triggered the nerve paralysis in this patient. Our report highlights the need for optimal management of comorbidities such as CODP as well as careful control of weight in HNPP patients to avoid potentially harmful complications.

A novel synonymous mutation in the MPZ gene causing an aberrant splicing pattern and Charcot-Marie-Tooth disease type 1b

Charcot-Marie-Tooth disease (CMT) is an inherited peripheral neuropathy with a heterogeneous genetic background. Here, we describe two CMT1B families with a mild sensory-motor neuropathy and a novel synonymous variant (c.309G > T, p.G103G) in exon 3 of the MPZ gene. Next generation sequencing analysis on a 94 CMT gene panel showed no mutations in other disease genes. In vitro splicing assay and mRNA expression analysis indicated that the c.309T variant enhances a cryptic donor splice site at position c.304 resulting in the markedly increased expression of the r.304_448del alternative transcript in patients' cells. This transcript is predicted to encode a truncated P0 protein (p.V102Cfs11*) lacking the transmembrane domain, thus suggesting a possible haploinsufficiency mechanism for this mutation. This is the third reported synonymous MPZ variant associated with CMT1 and affecting splicing. These data confirm the functional impact of synonymous variants on MPZ splicing and their possible role as disease-causing mutations rather than silent polymorphisms.

Novel outcome measures for Charcot-Marie-Tooth disease: validation and reliability of the 6-min walk test and StepWatch(™) Activity Monitor and identification of the walking features related to higher quality of life

BACKGROUND AND PURPOSE

Charcot-Marie-Tooth (CMT) disease is the most common inherited neuropathy, but therapeutic options have been limited to symptom management. Past pharmacological trials have failed, possibly due to insensitive outcome measures (OMs). The aim of the current study was to evaluate the validity and reliability of the 6-min walk test (6MWT) and StepWatch(™) Activity Monitoring (SAM) with other previously validated OMs in CMT disease.

METHODS

A prospective multicenter study was performed, consecutively enrolling 168 CMT patients (104 with CMT1A, 27 with CMT1B, 37 with X-linked CMT) from Italian centers specializing in CMT care.

RESULTS

Statistical analysis showed that the 6MWT was highly related with all previously used OMs. Some, but not all, SAM parameters were related to commonly used OMs but may provide more information about quality of life.

CONCLUSIONS

The current study demonstrated the validity and reliability of the 6MWT and SAM as OMs for CMT. Moreover, SAM provides data that correlate better with quality of life measures, making it useful in future rehabilitation trials.

Combined central and peripheral demyelination: Clinical features, diagnostic findings, and treatment

Combined central and peripheral demyelination (CCPD) is rare, and current knowledge is based on case reports and small case series. The aim of our study was to describe the clinical features, diagnostic results, treatment and outcomes in a large cohort of patients with CCPD. Thirty-one patients entered this retrospective, observational, two-center study. In 20 patients (65%) CCPD presented, after an infection, as myeloradiculoneuropathy, encephalopathy, cranial neuropathy, length-dependent peripheral neuropathy, or pseudo-Guillain-Barré syndrome. Demyelinating features of peripheral nerve damage fulfilling European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) electrodiagnostic criteria for CIDP were found in 23 patients (74%), and spatial dissemination of demyelinating lesions on brain MRI fulfilling the 2010 McDonald criteria for multiple sclerosis (MS) in 11 (46%). Two thirds of the patients had a relapsing or progressive disease course, usually related to the appearance of new spinal cord lesions or worsening of the peripheral neuropathy, and showed unsatisfactory responses to high-dose corticosteroids and intravenous immunoglobulins. The clinical presentation of CCPD was severe in 22 patients (71%), who were left significantly disabled. Our data suggest that CCPD has heterogeneous features and shows frequent post-infectious onset, primary peripheral nervous system or central nervous system involvement, a monophasic or chronic disease course, inadequate response to treatments, and a generally poor outcome. We therefore conclude that the current diagnostic criteria for MS and CIDP may not fully encompass the spectrum of possible manifestations of CCPD, whose pathogenesis remains largely unknown.

CMT subtypes and disease burden in patients enrolled in the Inherited Neuropathies Consortium natural history study: a cross-sectional analysis

BACKGROUND

The international Inherited Neuropathy Consortium (INC) was created with the goal of obtaining much needed natural history data for patients with Charcot-Marie-Tooth (CMT) disease. We analysed clinical and genetic data from patients in the INC to determine the distribution of CMT subtypes and the clinical impairment associated with them.

METHODS

We analysed data from 1652 patients evaluated at 13 INC centres. The distribution of CMT subtypes and pathogenic genetic mutations were determined. The disease burden of all the mutations was assessed by the CMT Neuropathy Score (CMTNS) and CMT Examination Score (CMTES).

RESULTS

997 of the 1652 patients (60.4%) received a genetic diagnosis. The most common CMT subtypes were CMT1A/PMP22 duplication, CMT1X/GJB1 mutation, CMT2A/MFN2 mutation, CMT1B/MPZ mutation, and hereditary neuropathy with liability to pressure palsy/PMP22 deletion. These five subtypes of CMT accounted for 89.2% of all genetically confirmed mutations. Mean CMTNS for some but not all subtypes were similar to those previously reported.

CONCLUSIONS

Our findings confirm that large numbers of patients with a representative variety of CMT subtypes have been enrolled and that the frequency of achieving a molecular diagnosis and distribution of the CMT subtypes reflects those previously reported. Measures of severity are similar, though not identical, to results from smaller series. This study confirms that it is possible to assess patients in a uniform way between international centres, which is critical for the planned natural history study and future clinical trials. These data will provide a representative baseline for longitudinal studies of CMT.

CLINICAL TRIAL REGISTRATION

ID number NCT01193075.

Is overwork weakness relevant in Charcot-Marie-Tooth disease?

BACKGROUND

In overwork weakness (OW), muscles are increasingly weakened by exercise, work or daily activities. Although it is a well-established phenomenon in several neuromuscular disorders, it is debated whether it occurs in Charcot-Marie-Tooth disease (CMT). Dominant limb muscles undergo a heavier overload than non-dominant and therefore if OW occurs we would expect them to become weaker. Four previous studies, comparing dominant and non-dominant hand strength in CMT series employing manual testing or myometry, gave contradictory results. Moreover, none of them examined the behaviour of lower limb muscles.

METHODS

We tested the OW hypothesis in 271 CMT1A adult patients by comparing bilateral intrinsic hand and leg muscle strength with manual testing as well as manual dexterity.

RESULTS

We found no significant difference between sides for the strength of first dorsal interosseous, abductor pollicis brevis, anterior tibialis and triceps surae. Dominant side muscles did not become weaker than non-dominant with increasing age and disease severity (assessed with the CMT Neuropathy Score); in fact, the dominant triceps surae was slightly stronger than the non-dominant with increasing age and disease severity.

DISCUSSION

Our data does not support the OW hypothesis and the consequent harmful effect of exercise in patients with CMT1A. Physical activity should be encouraged, and rehabilitation remains the most effective treatment for CMT patients.

Postural stabilization and balance assessment in Charcot-Marie-Tooth 1A subjects

The aim of the present study was to assess postural stabilization skill in adult subjects affected by Charcot-Marie-Tooth disease (CMT) type 1A. For this purpose ground reaction force (GRF) was measured by means of a piezoelectric force platform during the sit-to-stand (STS) movement, until a steady state erect posture was achieved. Specific indexes to quantify Centre of Mass acceleration, both during postural stabilization and during quiet standing, were computed using a mathematical model. Forty-seven CMT1A subjects were recruited for the study, and the control group was formed by forty-one age- and sex-matched healthy subjects. The results show that CMT1A subjects are less stable than controls during the quiet stance. Greater difficulty (high values of Yinf, the final instability rate) to maintain erect posture appears to be mainly associated with plantar-flexor muscle weakness, rather than to damage of the proprioceptive system. The worst performances shown by CMT1A subjects in the stabilization phase (high values of I, the global index of postural stabilization performance) seem to be associated with reduced muscle strength and the loss of large sensory nerve fibres. Distal muscle weakness appears to affect both postural stabilization and quiet erect posture. The presented protocol and the analysis of postural stabilization parameters provide useful information on CMT1A balance disorders.

Pendular nystagmus in hypomyelinating leukodystrophy

We report the case of a 49-year old woman affected by hypomyelinating leukodystrophy. She presented with typical pendular nystagmus that was analyzed with video-oculography which is provided in the supplementary material of the report. The pendular nystagmus was accompanied by upper limb ataxia on the index-to-nose test. The video was partly recorded with a slow-motion technique in order to better demonstrate the ataxia and the pendular nystagmus. The brain MRI demonstrated a characteristic pattern of hypomyelination. Pendular nystagmus is a key clinical sign that contributes to the diagnosis of CNS hypomyelination when a leukodystrophic pattern is observed on brain MRI.

Vitamin C and Charcot-Marie-Tooth 1A: Pharmacokinetic considerations

Charcot-Marie-Tooth 1A disease (CMT1A) is a disease for which no drug treatments are available. In 2004, it was reported that ascorbic acid reduced the severity of neuropathy in transgenic mice overexpressing PMP22, an animal model of human CMT1A, compared with untreated mice. Based on those results, clinical trials were undertaken at different centers worldwide and four of them have been completed, but none of them resulted in significant improvements. Based on the pharmacokinetics of ascorbic acid, we propose that the randomized clinical trial carried out thus far confirmed the tight control of ascorbic acid's absorption and proved its tolerability at one and two years. The pharmacokinetic considerations discussed in this article might largely explain the disappointing results of the recent CMT1A trials.

Gait pattern classification in children with Charcot-Marie-Tooth disease type 1A

Gait pattern classification may assist in clinical decision making and cluster analysis (CA) has been often adopted to this aim. The goal of this study was to identify, through CA, typical walking patterns in a group of 21 young subjects with CMT1A, a hereditary progressive neuropathy, and to study possible correlation with the disease's clinical status. The protocol included kinematic/kinetic analysis of natural walking and more demanding locomotor tasks, i.e. toe- and heel-walking. Hierarchical cluster analysis was carried out on parameters related to primary signs (foot-drop and push-off deficit) and, separately, to compensatory mechanisms at proximal (pelvis, hip and knee) or distal (ankle) level. CA on primary signs during natural walking identified three clusters: (1) pseudo-normal patients (PN), not significantly different from controls; (2) patients showing only foot-drop (FD); (3) patients with foot-drop and push-off deficit (FD&POD). Patients belonging to the PN subgroup showed distal abnormalities during heel-walking. The FD&POD subgroup was associated to a significantly worse clinical score (CMTES, p<0.05). The main compensatory strategies, which occurred independently from primary clusterization, included augmented hip/knee flexion in swing (steppage) and early ankle plantarflexion at mid stance (vaulting). We concluded that, although a number of young CMT1A patients do not show typical primary deviations during natural walking, they do show significant abnormalities in more demanding locomotor tasks that should be therefore considered. It is also hypothesized that progression of this degenerative condition may be associated to the migration of patients to more severe clusters, with possible appearance of compensatory strategies.

Recessive axonal Charcot-Marie-Tooth disease due to compound heterozygous mitofusin 2 mutations

OBJECTIVE

Mutations in mitofusin 2 (MFN2) are the most common cause of axonal Charcot-Marie-Tooth disease (CMT2). Over 50 mutations have been reported, mainly causing autosomal dominant disease, though families with homozygous or compound heterozygous mutations have been described. We present 3 families with early-onset CMT2 associated with compound heterozygous MFN2 mutations. Transcriptional analysis was performed to investigate the effects of the mutations.

METHODS

Patients were examined clinically and electrophysiologically; parents were also examined where available. Genetic investigations included MFN2 DNA sequencing and dosage analysis by multiplex ligation-dependent probe amplification. MFN2 mRNA transcripts from blood lymphocytes were analyzed in 2 families.

RESULTS

Compound heterozygosity for MFN2 mutations was associated with early-onset CMT2 of varying severity between pedigrees. Parents, where examined, were unaffected and were heterozygous for the expected mutations. Four novel mutations were detected (one missense, one nonsense, an intragenic deletion of exons 7 + 8, and a 3-base pair deletion), as well as 2 previously reported missense mutations. Transcriptional analysis demonstrated aberrant splicing of the exonic deletion and indicated nonsense-mediated decay of mutant alleles with premature truncating mutations.

CONCLUSIONS

Our findings confirm that MFN2 mutations can cause early-onset CMT2 with apparent recessive inheritance. Novel genetic findings include an intragenic MFN2 deletion and nonsense-mediated decay. Carrier parents were asymptomatic, suggesting that MFN2 null alleles can be nonpathogenic unless coinherited with another mutation.

Reliability of instrumented movement analysis as outcome measure in Charcot-Marie-Tooth disease: results from a multitask locomotor protocol

Some neurodegenerative diseases at early stage may not drastically affect basic gait ability, whereas more demanding locomotor tasks are more prone to disease-induced abnormalities. In this study, we evaluated the interday test-retest reliability, 4-6 weeks apart, of instrumented movement analysis on a group of 20 subjects with Charcot-Marie-Tooth (CMT) disease considering a set of kinematic and kinetic curves and related parameters obtained during natural walking (NW) and faster walking, heel and toe-walking, step ascending and descending. Results showed that the reliability was good for NW, with the exception of trunk curves, pelvic tilt and EMG profiles (moderate reliability), and trunk ROM in sagittal/transverse plane (poor reliability). Comparing our results with literature, CMT patients did not present a greater variability during NW than healthy subjects or patients with diseases of CNS. Additional locomotor tasks showed a slight reduction of reliability, although the moderate-to-good level shown in NW was almost never reduced to poor. Most of SEM values (absolute measurement errors) were smaller than 5°, a clinically acceptable threshold. In particular THS, an ankle joint related parameter computed across heel and toe-walking tasks, showed an optimal reliability (ICC=0.95, SEM=2.7°) and correlation with CMT clinical scores. Toe and heel-walking and step ascending tasks maximised the number of parameters with a moderate-to-good correlation with patients' clinical status. We concluded that, in addition to natural walking, more challenging locomotor tasks are good candidates to provide reliable and sensitive outcome measures for CMT patients.

Four novel cases of periaxin-related neuropathy and review of the literature

OBJECTIVE

To report 4 cases of autosomal recessive hereditary neuropathy associated with novel mutations in the periaxin gene (PRX) with a review of the literature. Periaxin protein is required for the maintenance of peripheral nerve myelin. Patients with PRX mutations have early-onset autosomal recessive demyelinating Charcot-Marie-Tooth disease (CMT4F) or Déjèrine-Sottas neuropathy (DSN). Only 12 different mutations have been described thus far.

METHODS

Case reports and literature review.

RESULTS

Four patients from 3 unrelated families (2 siblings and 2 unrelated patients) were affected by an early-onset, slowly progressive demyelinating neuropathy with relevant sensory involvement. All carried novel frameshift or nonsense mutations in the PRX gene. The 2 siblings were compound heterozygotes for 2 PRX null mutations (p.Q547X and p.K808SfsX2), the third patient harbored a homozygous nonsense mutation (p.E682X), and the last patient had a homozygous 2-nt insertion predicting a premature protein truncation (p.S259PfsX55). Electrophysiologic analysis showed a severe slowing of motor nerve conduction velocities (MNCVs, between 3 and 15.3 m/s) with undetectable sensory nerve action potentials (SNAPs). Sural nerve biopsy, performed in 2 patients, demonstrated a severe demyelinating neuropathy and onion bulb formations. Interestingly, we observed some variability of disease severity within the same family.

CONCLUSIONS

These cases and review of the literature indicate that PRX-related neuropathies have early onset but overall slow progression. Typical features are prominent sensory involvement, often with sensory ataxia; a moderate-to-dramatic reduction of MNCVs and almost invariable absence of SNAPs; and pathologic demyelination with classic onion bulbs, and less commonly myelin folding and basal lamina onion bulbs.

Late-onset sporadic ataxia, pontine lesion, and retroperitoneal fibrosis: a case of Erdheim-Chester disease

A 60-year-old man with progressive gait ataxia and mild pyramidal signs showed at MRI a pontine lesion with post-contrast enhancement in the left middle cerebellar peduncle. Diagnosis of Erdheim-Chester disease (ECD), a rare non-Langerhans cell histiocytosis, was suggested, further supported by a previously diagnosed retroperitoneal fibrosis. X-ray films demonstrated characteristic bilateral and symmetric osteosclerosis of the long bones of the lower limbs, which at radionuclide studies exhibited a marked increase in technetium-99 uptake. A cerebral 18FDG-PET showed a relevant pontine uptake of the tracer. Re-evaluation of a past retroperitoneal biopsy showed an intense CD68+, CD1a-, and S100- infiltrate of histiocytes with foamy cytoplasm, thus confirming the diagnosis. ECD should be regarded as a rare cause of adult-onset sporadic ataxia, especially when pontine lesions and extraneurological manifestations are present.

Can MR imaging diagnose adult-onset Alexander disease?

BACKGROUND AND PURPOSE

In recent years, the discovery that mutations in the glial fibrillary acidic protein gene (GFAP) were responsible for Alexander disease (AD) brought recognition of adult cases. The purpose of this study was to demonstrate that MR imaging allows identification of cases of AD with adult onset (AOAD), which are remarkably different from infantile cases.

MATERIALS AND METHODS

In this retrospective study, brain and spinal cord MR imaging studies of 11 patients with AOAD (7 men, 4 women; age range, 26-64 years; mean age, 43.6 years), all but 1 genetically confirmed, were reviewed. Diffusion and spectroscopic investigations were available in 6 patients each.

RESULTS

Atrophy and changes in signal intensity in the medulla oblongata and upper cervical spinal cord were present in 11 of 11 cases and were the diagnostic features of AOAD. Minimal to moderate supratentorial periventricular abnormalities were seen in 8 patients but were absent in the 3 oldest patients. In these patients, postcontrast enhancement was also absent. Mean diffusivity was not altered except in abnormal white matter (WM). Increase in myo-inositol (mIns) was also restricted to abnormal periventricular WM.

CONCLUSIONS

Awareness of the MR pattern described allows an effective selection of the patients who need genetic investigations for the GFAP gene. This MR pattern even led to identification of asymptomatic cases and should be regarded as highly characteristic of AOAD.

POEMS syndrome: relapse after successful autologous peripheral blood stem cell transplantation

We report a patient with POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal gammopathy, Skin changes) treated with high dose chemotherapy and auto-Peripheral Blood Stem Cell Transplantation (auto-PBSCT) who had a very good response with complete clinical remission. Seven years later, she relapsed and a new sclerotic bone lesion was found. To our knowledge, this is the first POEMS syndrome relapse after successful auto-PBSCT.

Reliability of clinical outcome measures in Charcot-Marie-Tooth disease

We assessed inter- and intra-rater reliability of outcome measures in Charcot-Marie-Tooth disease (CMT) patients. In 40 CMT patients, we assessed reliability of Overall Neuropathy Limitations Scale (ONLS), 10-m timed walk (T10MW), 9-hole-peg test (9-HPT), maximal voluntary isometric contraction (MVIC) of arm (elbow flexion, hand-grip, and three-point pinch) and leg (knee extension, foot dorsiflexion/plantar flexion). Reliability was substantial for ONLS, excellent for T10MW and 9-HPT. For MVIC, inter and intra-rater reliability was excellent for hand contractions; for leg contractions, intra-rater agreement was moderate to substantial, whereas inter-rater agreement was poor. An ad hoc device was produced to immobilize the foot and MVIC reliability was re-assessed in 26 CMT patients, resulting in excellent inter-rater and intra-rater reliability for foot dorsiflexion, and clear inter-rater improvement for foot plantar flexion. All outcome measures appear adequate for CMT assessment. Use of an immobilization device improves foot MVIC reliability, preventing biased findings in patients with greater strength.

GFAP mutations and polymorphisms in 13 unrelated Italian patients affected by Alexander disease

Alexander disease (AD), a rare neurodegenerative disorder of the central nervous system, is characterized by the accumulation of cytoplasmic protein aggregates (Rosenthal fibers) composed of glial fibrillary acidic protein (GFAP) and small heat-shock proteins within astrocytes. To date, more than 40 different GFAP mutations have been reported in AD. The present study is aimed at the molecular diagnosis of Italian patients suspected to be affected by AD. By analyzing the GFAP gene of 13 unrelated patients (eight with infantile form, two with juvenile form and three with adult form), we found 11 different alleles, including four new ones. Among the novel mutations, three (p.R70Q, p.R73K, and p.R79P) were identified in exon 1 and p.L359P in exon 6. The sequence analysis also detected six different single nucleotide polymorphic variants, including two previously unreported ones, spread throughout non-coding regions (introns 2, 3, 5, 6, and 3'UTR) of the gene. All patients were heterozygous for the mutations, thus confirming their dominant effect.

Variables influencing quality of life and disability in Charcot Marie Tooth (CMT) patients: Italian multicentre study

The purpose of this study was to assess the variables that influence quality of life (QoL) and disability in patients with Charcot-Marie-Tooth disease (CMT). We performed a prospective multicentre study using validated clinical disability and QoL measurements. Multivariate analysis was performed using QoL as a dependent variable and duration of symptoms, age, gender and CMT type, depression and disability measurements as independent variables. We enrolled 211 patients. QoL was highly significantly deteriorated with respect to the Italian normative sample. The physical aspect of QoL was mainly related to disability but it does not increase with the age, probably because of an adaptation between expectation and reality. The mental QoL is influenced by depression (hence we have to consider this aspect approaching CMT patients). Moreover, we observed that women complained of more severe symptoms than men. Finally, some CMT subtypes are related to more severe bodily pain symptoms than others. Multiperspective assessment of CMT showed new aspects of this disease, mainly regarding (1) differences between men and women and (2) the crucial role of pain and depression.

Novel mutations in the HSN2 gene causing hereditary sensory and autonomic neuropathy type II

Hereditary sensory and autonomic neuropathy type II (HSAN-II) is caused by recessive mutations in the HSN2 gene assigned to chromosome 12p13.33. The authors report three unrelated HSAN-II families with homozygous or compound heterozygous mutations resulting in the truncation of the HSN2 protein. Genotype-phenotype correlations indicated that HSN2 mutations are associated with an early childhood onset of a predominantly sensory neuropathy, complicated by acromutilations in both upper and lower limbs.