Failure to find P50 suppression deficits in young first-episode patients with schizophrenia and clinically unaffected siblings

OBJECTIVE

To evaluate whether the P50 gating deficit is present in young first-episode patients with schizophrenia and their healthy young siblings.

METHODS

An auditory paired-click paradigm was used to assess P50 gating in 53 patients, 27 unaffected siblings, and 28 healthy controls. P50 parameters were compared between patients, sibs, and unrelated controls by a mixed-effects regression model.

RESULTS

P50 gating was not significantly impaired in patients with schizophrenia and healthy siblings as compared with controls.

CONCLUSIONS

P50 gating was not found to be significantly impaired in young first-episode schizophrenia patients and in healthy young siblings. These results are in contrast with the existing literature. We suggest that P50 gating impairment may be developmentally or age dependent.

Decreased cortical inhibition and yet cerebellar pathology in ‘familial cortical myoclonic tremor with epilepsy’

Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar Purkinje cell degeneration and a normal sensorimotor cortex. Subsequently, we sought to explore the nature of cerebellar and motor system pathophysiology in FCMTE. Eye movement recordings and transcranial magnetic stimulation performed in six related FCMTE patients showed impaired saccades and smooth pursuit and downbeat nystagmus upon hyperventilation, as in patients with spinocerebellar ataxia type 6. In FCMTE patients short-interval intracortical inhibition (SICI) was significantly reduced. Resting motor threshold, recruitment curve, silent period, and intracortical facilitation were normal. The neuropathological and ocular motor abnormalities indicate cerebellar involvement in FCMTE patients. Decreased SICI is compatible with intracortical GABA(A)-ergic dysfunction. Cerebellar and intracortical functional changes could result from a common mechanism such as a channelopathy. Alternatively, decreased cortical inhibition may be caused by dysfunction of the cerebello-thalamo-cortical loop as a result of primary cerebellar pathology.

Sensory integration in writer's cramp: comparison with controls and evaluation of botulinum toxin effect

OBJECTIVE

Abnormal temporal and spatial sensory integration have been described in mixed groups of dystonic patients. We tested somatosensory integration and the effect of botulinum toxin (BoNT) in patients with writer's cramp (WC).

METHODS

Median and ulnar SEPs were recorded in 29 WC patients and in 10 controls. We performed: individual and simultaneous stimulation of median and ulnar nerves (MU) and paired stimulation of median nerve at interstimulus-interval (ISI) of 40 and 100 ms. All the trials were repeated after blinded randomized treatment with placebo or BoNT-A.

RESULTS

We found no differences between patients and controls in standard SEPs. Spatial (except for N9) and temporal suppression after ISI 40 were present in both groups for all the waves; after ISI 100, suppression was present only for N70. There were no differences between patients and controls. After BoNT-A treatment, no changes were observed.

CONCLUSIONS

In contrast with previous findings in heterogeneous dystonic groups, and although some studies suggest impairment of spatial and temporal sensory discrimination in patients with focal dystonia, in our large cohort of patients with WC we found no evidence of abnormal somatosensory integration investigated by means of SEPs and no changes in somatosensory variables after BoNT-A treatment.

SIGNIFICANCE

Our findings may suggest pathophysiological differences between focal and generalized dystonia, and may also point to an inferior sensitivity of SEPs in detecting abnormalities in sensory discrimination as compared to methods based on subjective discrimination.

Phenotype of Charcot-Marie-Tooth disease Type 2

OBJECTIVE

To investigate the clinical and electrophysiologic phenotype of Charcot-Marie-Tooth disease (CMT) Type 2 in a large number of affected families.

METHODS

We excluded CMT Type 1, hereditary neuropathy with liability to pressure palsies, and CMT due to Cx32 gene mutations by DNA analysis. We performed genetic analysis of the presently known CMT Type 2 genes.

RESULTS

Sixty-one persons from 18 families were affected. Ninety percent of patients were able to walk with or without the help of aids. Proximal leg muscle weakness was present in 13%. Asymmetrical features were present in 15%. Normal or brisk knee reflexes were present in 36%. Extensor plantar responses without associated spasticity occurred in 10 patients from eight families. Only three causative mutations were identified in the MFN2, BSCL2, and RAB7 genes. No mutations were found in the NEFL, HSPB1, HSPB8, GARS, DNM2, and GDAP1 genes.

CONCLUSIONS

At group level, the clinical phenotype of Charcot-Marie-Tooth disease (CMT) Type 2 is uniform, with symmetric, distal weakness, atrophy and sensory disturbances, more pronounced in the legs than in the arms, notwithstanding the genetic heterogeneity. Brisk reflexes, extensor plantar responses, and asymmetrical muscle involvement can be considered part of the CMT Type 2 phenotype. The causative gene mutation was found in only 17% of the families we studied.

Local field potentials and oscillatory activity of the internal globus pallidus in myoclonus-dystonia

The pathophysiology of myoclonus-dystonia (M-D), an autosomal dominantly inherited movement disorder characterized by myoclonic jerks and dystonic contractions, is largely unknown. In the present study, local field potential (LFP) activities in the globus pallidus internus (GPi) from two genetically proven M-D patients are investigated. Coherence analysis between GPi LFP activity and electromyographic muscle activity (EMG) and synchronization of GPi neuronal activity using event-related spectral perturbation (ERSP) in a go-no-go paradigm were studied. Significant increased coherence in the 3 to 15 Hz frequency band was detected between GPi LFP activity and several muscles, with the LFP leading the muscles. The ERSP analysis revealed synchronization in the 3 to 15 Hz frequency band within the GPi before the imperative cue of the go-no-go task and desynchronization in the same band after the cue. The LFP recordings of the GPi in M-D show that the low-frequency band previously described in dystonia is also involved in the dystonia plus syndrome M-D. The 3 to 15 Hz synchronization in the go-no-go paradigm has not been described previously and may point to the existence of (myoclonus-)dystonia specific oscillatory activity in the GPi.

Botulinum toxin for writer's cramp: a randomised, placebo-controlled trial and 1-year follow-up

BACKGROUND

Botulinum toxin type A (BoNT-A) has become the treatment of choice for most types of focal dystonia.

OBJECTIVE

To investigate the efficacy of BoNT-A injections in patients with writer's cramp in a double-blind, randomised, placebo-controlled trial and to evaluate the follow-up results.

METHODS

Forty participants were randomised to treatment with either BoNT-A or placebo injections in two sessions. Trial duration was 12 weeks. The primary outcome measure was the patients' choice to continue with the treatment, despite its possible disadvantages. Secondary outcome measures included several clinical rating scales on the levels of impairment and disability. Assessments were made at baseline and 2 months (secondary outcomes) and 3 months (primary outcome). Duration of follow-up was 1 year.

RESULTS

39 patients completed the trial. Fourteen of 20 patients (70%) receiving BoNT-A reported a beneficial effect and chose to continue treatment, versus 6 of 19 patients (31.6%) in the placebo group (p = 0.03). The changes on most of the clinical rating scales were significantly in favour of BoNT-A. Side effects reported were hand weakness, which was mostly mild and always transient, and pain at the injection site. After 1 year, 20 of 39 patients were still under treatment with a positive effect.

CONCLUSION

Treatment with BoNT-A injections led to a significantly greater improvement compared with placebo, according to patients' opinion and clinical assessment scales. Weakness in the hand is an important side effect of BoNT-A injections, but despite this disadvantage, most patients preferred to continue treatment. About 50% of our patients were still under treatment after 1 year.

Abnormal low frequency drive in myoclonus-dystonia patients correlates with presence of dystonia

The pathophysiology of Myoclonus-Dystonia (M-D), an autosomal dominantly inherited movement disorder is largely unknown. In different forms of dystonia abnormal intermuscular coherence is present. The objective of this study was to investigate whether the myoclonic and dystonic features are the result of an abnormal common drive to the muscles in M-D. Coherence analysis was performed in 20 DYT11 mutation carriers (MC) and 13 healthy controls during resting condition and during weak isometric contraction of the arm and neck. The EMG-EMG coherence analysis showed significantly increased intermuscular 3 to 10 Hz coherence in 4 DYT11 MC with clinical pronounced (mobile and static) dystonia. This coherence was not present in DYT11 MC with mild (static) dystonia and/or predominating myoclonus. The EEG-EMG analysis showed significant 15 to 30 Hz coherence during weak isometric contraction of the arm in five healthy controls, but in none of the DYT11 MC. The intermuscular coherence in the low frequency band in DYT11 MC with predominant dystonia is concordant with the previously described coherence in dystonia and suggests that the pathophysiology of M-D shares common pathophysiological features with dystonia. The absence of 15 to 30 Hz EEG-EMG coherence in DYT11 MC may reflect abnormal motor activation caused by an altered cortical drive because of the basal ganglia dysfunction.

Median nerve conduction velocity and central conduction time measured with somatosensory evoked potentials in thyroxine-treated infants with Down syndrome

OBJECTIVE

The aim of this study was to determine whether thyroxine treatment would improve nerve conduction in infants with Down syndrome.

METHODS

A single-center, nationwide, randomized, double-blind, clinical trial was performed. Neonates with Down syndrome were assigned randomly to thyroxine (N = 99) or placebo (N = 97) treatment for 2 years. Daily thyroxine doses were adjusted regularly to maintain plasma thyrotropin levels in the normal range and free thyroxine concentrations in the high-normal range. The outcome measures were nerve conduction velocity and central conduction time, determined through median nerve somatosensory evoked potential recording, at the age of 24 months.

RESULTS

At the age of 24 months, somatosensory evoked potential recordings for 81 thyroxine-treated and 84 placebo-treated infants were available for analysis. Nerve conduction velocity and central conduction time did not differ significantly between the 2 treatment groups (nerve conduction velocity: thyroxine: 51.0 m/second; placebo: 50.1 m/second; difference: 0.9 m/second; central conduction time: thyroxine: 8.83 milliseconds; placebo: 8.73 milliseconds; difference: 0.1 milliseconds).

CONCLUSIONS

Postnatal thyroxine treatment of infants with Down syndrome did not alter somatosensory evoked potential-measured peripheral or central nerve conduction significantly. The absence of favorable effects suggests that pathologic mechanisms other than mild postnatal hypothyroidism underlie the impaired nerve conduction. The absence of adverse effects suggests that longstanding plasma free thyroxine concentrations in the high-normal range are not harmful to nerve maturation.

Comparison of CMT1A and CMT2: similarities and differences

To evaluate the clinical and electrophysiological similarities and differences between two large groups of patients with Charcot-Marie-Tooth disease, i.e. CMT1A and CMT2, we performed a post hoc comparison of clinical and electrophysiological data. Most CMT1A and CMT2 patients had the classical CMT phenotype. Age of onset was significantly later in CMT2. Total areflexia was present in approximately half of the CMT1A patients whereas it was rare in CMT2. Foot deformities and weakness of knee extensor and foot dorsal flexor muscles were more frequent in CMT1A. Median nerve motor nerve conduction velocities (MNCV) were always less than 38 m/s in CMT1A patients, whereas this was also the case in 16% of the CMT2 patients. Sensory nerve conduction velocities showed less overlap. In both CMT1A and CMT2 CMAP and SNAP amplitudes were often reduced or not obtainable in the legs. In CMT1A, SNAP amplitude was more reduced and SNAP duration more prolonged than in CMT2. We conclude that there are no robust clinical signs or symptoms that differentiate between CMT1A and CMT2 patients. Electrodiagnostical studies show a length-dependent motor and sensory axonal dysfunction in both CMT-types. Additional SNAP and SNCV evaluation may be helpful in focusing molecular genetic analysis in the occasional case of CMT2 showing slow motor nerve conduction velocities overlapping with CMT1A values. The reduction of CMAP and SNAP amplitudes in CMT1A is probably a combined effect of demyelination and axonal dysfunction.

SSEPs and prognosis in postanoxic coma: Only short or also long latency responses?

BACKGROUND

Short latency somatosensory evoked potential (SSEP) (N20) is a good predictor of poor outcome in postanoxic coma. It has been suggested that the long latency response (N70) may increase the sensitivity of SSEPs for predicting poor outcome.

METHODS

As part of a prospective cohort study in 407 adult patients unconscious 24 hours after cardiopulmonary resuscitation (CPR), N20 was recorded 24, 48, and 72 hours after CPR, and N70 was recorded at least once in 319 patients. Poor outcome was defined as death or persistent vegetative state 1 month after CPR.

RESULTS

Absent N20 had a 0% false positive test rate at all time intervals, with prevalence of poor test result varying from 37 to 48%. Addition of abnormal N70 (absent or delayed > 130 msec) with present N20 as poor test result added 21 to 28% to this prevalence, but at the cost of a false positive test rate of 4 to 15%. Good outcome could not be predicted reliably with either of the tests, as only 28% of patients with normal N20 and N70 had a good outcome.

CONCLUSION

Determination of presence or absence of the N70 in patients with postanoxic coma gives additional information about the likelihood of poor outcome, but it is not precise enough to base treatment decisions solely on its absence.

Interobserver variation in the interpretation of SSEPs in anoxic–ischaemic coma

OBJECTIVE

To study interobserver variation in the interpretation of median nerve SSEPs in patients with anoxic-ischaemic coma.

METHODS

SSEPs of 56 consecutive patients with anoxic-ischaemic coma were interpreted independently by 5 experienced clinical neurophysiologists using guidelines derived from a pilot study. Interobserver agreement was expressed as kappa coefficients.

RESULTS

Kappa ranged from 0.20 to 0.65 (mean 0.52, SD 0.14). Disagreement was related with noise level and failure to adhere strictly to the guidelines in 15 cases. The presence or absence of N13 and cortical peaks caused disagreement in 5 cases each. For recordings with a noise level of 0.25 microV or more, mean kappa was 0.34; for recordings with a noise level below 0.25 microV mean kappa was 0.74.

CONCLUSIONS

Interobserver agreement for SSEPs in anoxic-ischaemic coma was only moderate. Since the noise level strongly influenced interobserver variation, utmost attention should be given to its reduction. If an artefact level over 0.25 microV remains, absence of N20 cannot be judged with sufficient certainty and the SSEP should be repeated at a later stage.

SIGNIFICANCE

Because of its moderate interobserver agreement, great care has to be given to accurate recording and interpretation of SSEPs before using the recordings for non-treatment decisions.

Late onset axonal Charcot-Marie-Tooth phenotype caused by a novel myelin protein zero mutation

A late onset axonal Charcot-Marie-Tooth phenotype is described, resulting from a novel mutation in the myelin protein zero (MPZ) gene. Comparative computer modelling of the three dimensional structure of the MPZ protein predicts that this mutation does not cause a significant structural change. The primary axonal disease process in these patients points to a function of MPZ in maintenance of the myelinated axons, apart from securing stability of the myelin layer.

The auditory startle response in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) patients are considered to have excessive EMG responses in the orbicularis oculi (OO) muscle and excessive autonomic responses to startling stimuli. The aim of the present study was to gain more insight into the pattern of the generalized auditory startle reflex (ASR). Reflex EMG responses to auditory startling stimuli in seven muscles rather than the EMG response of the OO alone as well as the psychogalvanic reflex (PGR) were studied in PTSD patients and healthy controls. Ten subjects with chronic PTSD (>3 months) and a history of excessive startling and 11 healthy controls were included. Latency, amplitude and duration of the EMG responses and the amplitude of the PGR to 10 auditory stimuli of 110 dB SPL were investigated in seven left-sided muscles. The size of the startle reflex, defined by the number of muscles activated by the acoustic stimulus and by the amplitude of the EMG response of the OO muscle as well, did not differ significantly between patients and controls. Median latencies of activity in the sternocleidomastoid (SC) (patients 80 ms; controls 54 ms) and the deltoid (DE) muscles (patients 113 ms; controls 69 ms) were prolonged significantly in PTSD compared to controls (P < 0.05). In the OO muscle, a late response (median latency in patients 308 ms; in controls 522 ms), probably the orienting reflex, was more frequently present in patients (56%) than in controls (12%). In patients, the mean PGR was enlarged compared to controls (P < 0.05). The size of the ASR response is not enlarged in PTSD patients. EMG latencies in the PTSD patients are prolonged in SC and DE muscles. The presence of a late response in the OO muscle discriminates between groups of PTSD patients with a history of startling and healthy controls. In addition, the autonomic response, i.e. the enlarged amplitude of the PGR can discriminate between these groups.

Prediction of poor outcome within the first 3 days of postanoxic coma

OBJECTIVE

To determine the optimal timing of somatosensory evoked potential (SSEP) recordings and the additional value of clinical and biochemical variables for the prediction of poor outcome in patients who remain comatose after cardiopulmonary resuscitation (CPR).

METHODS

A prospective cohort study was conducted in 32 intensive care units including adult patients still unconscious 24 hours after CPR. Clinical, neurophysiologic, and biochemical variables were recorded 24, 48, and 72 hours after CPR and related to death or persisting unconsciousness after 1 month.

RESULTS

Of 407 included patients, 356 (87%) had a poor outcome. In 301 of 305 patients unconscious at 72 hours, at least one SSEP was recorded, and in 136 (45%), at least one recording showed bilateral absence of N20. All these patients had a poor outcome (95% CI of false positive rate 0 to 3%), irrespective of the timing of SSEP. In the same 305 patients, neuron-specific enolase (NSE) was determined at least once in 231, and all 138 (60%) with a value >33 microg/L at any time had a poor outcome (95% CI of false positive rate 0 to 3%). The test results of SSEP and NSE overlapped only partially. The performance of all clinical tests was inferior to SSEP and NSE testing, with lower prevalences of abnormal test results and wider 95% CI of false positive rates.

CONCLUSION

Poor outcome in postanoxic coma can be reliably predicted with somatosensory evoked potentials and neuron-specific enolase as early as 24 hours after cardiopulmonary resuscitation in a substantial number of patients.

Coherence analysis differentiates between cortical myoclonic tremor and essential tremor

Familial cortical myoclonic tremor with epilepsy (FCMTE) is characterized by a distal kinetic tremor, infrequent epileptic attacks, and autosomal dominant inheritance. The tremor is thought to originate from the motor cortex. In our patient group, a premovement cortical spike could not be established on electroencephalogram (EEG) back-averaging. Corticomuscular and intermuscular coherence analysis can demonstrate a cortical common drive to muscles. We carried out coherence analysis of electromyography (EMG) of forearm muscles and EEG of contralateral motor cortex in 7 FCMTE patients, 8 essential tremor (ET) patients, and 7 healthy controls. Results showed strong cortico- and intermuscular coherence in the 8- to 30-Hz range in the FCMTE patients, with EEG preceding EMG. Healthy controls and ET patients showed normal weak coherence around 20 Hz. The ET patients showed some additional coherence at tremor frequency (6 Hz), probably the result of sensory information flowing back to the sensorimotor cortex. These findings point to a pathological cortical drive in FCMTE patients leading to tremulous movements. Coherence analysis is an easy and useful method to differentiate FCMTE from ET. Coherence analysis is helpful when investigating a cortical common drive in cortical tremor and other movement disorders.

Familial cortical myoclonic tremor with epilepsy: A single syndromic classification for a group of pedigrees bearing common features

Fifty Japanese and European families with cortical myoclonic tremor and epilepsy have been reported under various names. Unfamiliarity with the syndrome often leads to an initial misdiagnosis of essential tremor or progressive myoclonus epilepsy. A detailed overview of the literature is lacking and is the scope of this study. Disease characteristics are adult onset, distal action tremor and myoclonus, epileptic seizures, autosomal dominant inheritance, benign course, effectiveness of antiepileptic drugs, and possibly cognitive decline. A channelopathy is hypothesized to be the basis of the disease. Despite phenotypic and genetic differences between the Japanese and European pedigrees, the clinical and electrophysiological data point toward one syndrome. To avoid confusion in literature and possible misdiagnosis of patients, we propose to use one description and suggest "familial cortical myoclonic tremor with epilepsy" (FCMTE). In addition, we put forward diagnostic criteria to give a starting point from which to conduct genetic studies.

Clinical disease severity and axonal dysfunction in hereditary motor and sensory neuropathy Ia

BACKGROUND

Hereditary motor and sensory neuropathy type Ia (HMSN Ia) is known as a primarily demyelinating peripheral nerve disease. Evidence is accumulating that axonal involvement determines the course of the disease process.

METHODS

Fifty-one patients were investigated. Physical disability and impairments were scored. Nerve conduction velocities (NCVs) were used as indirect measures for myelination status and compound muscle/sensory nerve action potential (CMAP/SNAP) amplitudes served as indirect measures for axonal function.

RESULTS

Median age was 39 years (range 6-69). Muscle weakness and sensory dysfunction was more severe in the legs than in the arms and distally more than proximally. However, more than 40% of the patients had proximal muscle weakness in the legs. Three point grip was used as representative of combined distal arm muscle groups. CMAP amplitude was the most important independent variable in a multiple linear regression model (forward selection) to explain the relation between three point grip strength and four different features, i. e., CMAP amplitude of the abductor pollicis brevis, median nerve MNCV, gender, and duration of signs and symptoms. The severity of axonal dysfunction was nerve length-dependent and was related to the myelination status. The mild physical disability due to both muscle weakness and sensory dysfunction was also related to axonal dysfunction.

CONCLUSIONS

In HMSN Ia, clinical disease severity at the impairment and disability levels is related to the severity of axonal dysfunction. Our data support the hypothesis that the myelination status is one of the factors that determine the extent of axonal dysfunction later in life. Proximal weakness of the legs is encountered in a considerable proportion of our patients.

Propriospinal myoclonus after treatment with ciprofloxacin

The clinical and electrophysiological features of a truncal myoclonus in a 55-year-old man are described. The electromyographic characteristics point toward propriospinal myoclonus. It is suggested that a myoclonic generator was released after use of ciprofloxacin, by antagonising the gamma-aminobutyric acid metabolism.

Hereditary myoclonus-dystonia associated with epilepsy

A five-generation Dutch family with inherited myoclonus-dystonia (M-D) is described. Genetic analysis revealed a novel truncating mutation within the epsilon-sarcoglycan gene (SGCE). In three of five gene carriers, epilepsy and/or EEG abnormalities were associated with the symptoms of myoclonus and dystonia. The genetic and clinical heterogeneity of M-D is extended. EEG changes and epilepsy should not be considered exclusion criteria for the clinical diagnosis of M-D.

Clinical and neuropsychological correlates of the P300 in schizophrenia

We investigated the relationship between the P300, neuropsychological test performance and symptomatology in recent-onset schizophrenic patients (n = 45) to gain insight into underlying mechanisms of abnormal P300 in schizophrenia. The P300 was recorded in two sessions with an intermission of five minutes, at the midline frontal, central and parietal electrode site. P300 amplitude and latency were compared with those obtained in 25 controls. Twenty patients were treated with olanzapine and 19 patients with risperidone. P300 amplitude was smaller and latency longer in patients than in controls. In the patient group, parietal P300 amplitude reduction was related to poorer performance on neuropsychological tests of memory. Frontal P300 amplitude reduction was related to impaired selective attention. In patients with negative symptomatology, P300 amplitude was reduced in the second P300 session compared with the first. Patients on risperidone demonstrated a smaller parietal P300 amplitude than patients using olanzapine. Reduced parietal P300 amplitude could signify a dysfunction in the continuous memory updating of current events. Negative symptomatology may be associated with a time dependent decrease in neuronal firing, as indicated by reduced P300 amplitude in the second P300 session.

Thixotropy of levator palpebrae as the cause of lagophthalmos after peripheral facial nerve palsy

Patients with facial nerve palsy are at risk of developing corneal ulceration because of lagophthalmos (incomplete closure of the affected eyelid). Lagophthalmos could result from thixotropy of the levator palpebrae muscle--that is, the formation of tight crossbridges between the actin and myosin filaments of the muscle fibres causing stiffness of the muscle--rather than from paralysis of the orbicularis occuli muscle as previously supposed. This possibility was investigated in 13 patients with a peripheral facial nerve palsy in a prospective open study. The levator muscle of the affected eyelid was stretched by manipulation and downward movement of the passively closed upper eyelid for approximately 15 seconds. The amount of lagophthalmos was measured before and immediately after this manoeuvre. In all patients except one there was a clear reduction in lagophthalmos (mean reduction 72%; range 60-100%). Thus in this setting the lagophthalmos appears to be caused by thixotropy of the levator palpebrae muscle, which has implications for treatment.

Two amino-acid substitutions in the myelin protein zero gene of a case of Charcot-Marie-Tooth disease associated with light-near dissociation

Charcot-Marie-Tooth disease caused by mutations of the myelin protein zero gene demonstrates considerable phenotypical variability. We describe a 45-year-old female with a peripheral neuropathy with demyelinating and axonal features, pes cavus and pupillary light-near dissociation. She was heterozygous for two mutations in the myelin protein zero gene (His81Tyr and Val113Phe), both present on the same allele. Our patient shows a less severe phenotype than previously described patients with a His81Arg mutation. Multiple mutations in the myelin protein zero gene, as well as Charcot-Marie-Tooth with pupillary abnormalities have previously been described in rare instances. However, concurrent occurrence of both phenomena is a novel finding.