EGR2 gene-linked hereditary neuropathies present with a bimodal age distribution at symptoms onset

BACKGROUND

Mutations in the Early-Growth Response 2 (EGR2) gene cause various hereditary neuropathies, including demyelinating Charcot-Marie-Tooth (CMT) disease type 1D (CMT1D), congenital hypomyelinating neuropathy type 1 (CHN1), Déjerine-Sottas syndrome (DSS), and axonal CMT (CMT2).

METHODS

In this study, we identified 14 patients with heterozygous EGR2 mutations diagnosed between 2000 and 2022.

RESULTS

Mean age was 44 years (15-70), 10 patients were female (71%), and mean disease duration was 28 years (1-56). Disease onset was before age 15 years in nine cases (64%), after age 35 years in four cases (28%), and one patient aged 26 years was asymptomatic (7%). All symptomatic patients had pes cavus and distal lower limbs weakness (100%). Distal lower limbs sensory symptoms were observed in 86% of cases, hand atrophy in 71%, and scoliosis in 21%. Nerve conduction studies showed a predominantly demyelinating sensorimotor neuropathy in all cases (100%), and five patients needed walking assistance after a mean disease duration of 50 years (47-56) (36%). Three patients were misdiagnosed as inflammatory neuropathy and treated with immunosuppressive drugs for years before diagnosis was corrected. Two patients presented with an additional neurologic disorder, including Steinert's myotonic dystrophy and spinocerebellar ataxia (14%). Eight EGR2 gene mutations were found, including four previously undescribed.

INTERPRETATION

Our findings demonstrate EGR2 gene-related hereditary neuropathies are rare and slowly progressive demyelinating neuropathies with two major clinical presentations, including a childhood-onset variant and an adult-onset variant which may mimic inflammatory neuropathy. Our study also expands the genotypic spectrum of EGR2 gene mutations.

Spinal cord lesion mimicking a dysimmune myelitis revealing CANVAS syndrome

CONTEXT

Posterior spinal cord lesions are found in patients with ganglionopathy. These are normally found in later stages of the neuronopathy as a consequence of dorsal root ganglia degeneration. Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome (CANVAS) is an emerging neurological disorder. Myelitis lesions have been described in confirmed CANVAS cases.

FINDINGS

We describe a case of a 68-year-old woman with slowly progressive ataxia with paresthesia. Laboratory tests were normal. Total spine MRI showed a C4 posterior spinal cord lesion. Lumbar puncture was positive for oligoclonal bands with normal IgG index and protein level. Paraneoplastic antibodies were not detected. Electromyography showed nonlength dependent sensory neuropathy. The patient was treated with intravenous immunoglobulin for suspected dysimmune myelitis. Over 6 years, she progressively developed other neurological manifestations evoking CANVAS. Nerve conduction study showed isolated sensory impairment over the years and peripheral nerve ultrasound revealed abnormally small nerves. Further genetic testing confirmed the diagnosis.

CONCLUSION

This is the first case of CANVAS syndrome presenting initially with an isolated spinal cord lesion mimicking dysimmune myelitis. The purpose of this case report is to add to the current literature about this evolving neurological syndrome and to aid clinicians in their diagnostic approach in clinical practice.

Protocol of comparison of the effects of single plasma exchange and double filtration plasmapheresis on peripheral lymphocyte phenotypes in patients with Chronic Inflammatory Demyelinating Polyradiculoneuropathy: a monocentric prospective study with single-case experimental design

BACKGROUND

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP), a rare disorder affecting young adults, causes gradual weakness of the limbs, areflexia and impaired sensory function. New CIDP phenotypes without pathogenic antibodies but with modified cell profiles have been described. Treatments include corticotherapy, intravenous immunoglobulins, and plasmapheresis but the latter's action mechanisms remain unclear. Plasmapheresis supposedly removes toxic agents like antibodies from plasma but it is uncertain whether it has an immune-modulating effect. Also, the refining mechanisms of the two main plasmapheresis techniques-single plasma exchange and double filtration plasmapheresis (DFPP) - are different and unclear. This study aims to compare the evolution of peripheral lymphocyte profiles in patients with CIDP according to their treatment (single centrifugation plasmapheresis or DFPP) to better grasp the action mechanisms of both techniques.

METHOD

In this proof-of-concept, monocentric, prospective, Single-Case Experimental Design study, 5 patients are evaluated by alternating their treatment type (single plasma exchange or DFPP) for 6 courses of treatment after randomization to their first treatment type. Each course of treatment lasts 2-4 weeks. For single plasma exchange, 60 ml/kg plasma will be removed from the patient and replaced with albumin solutes, with a centrifugation method to avoid the immunological reaction caused by the membrane used with the filtration method. For DFPP, 60 ml/kg plasma will be removed from the patient with a plasma separator membrane, then processed via a fractionator membrane to remove molecules of a greater size than albumin before returning it to the patient. This technique requires no substitution solutes, only 20 g of albumin to replace what would normally be lost during a session. The primary outcome is the difference between the two plasmapheresis techniques in the variation of the TH1/TH17 ratio over the period D0H0-D0H3 and D0H0-D7. Secondary outcomes include the variation in lymphocyte subpopulations at each session and between therapeutic plasmapheresis techniques, the clinical evolution, tolerance and cost of treatments.

DISCUSSION

Understanding the action mechanisms of single plasma exchange and DFPP will help us to offer the right treatment to each patient with CIPD according to efficacy, tolerance and cost.

TRIAL REGISTRATION

ClinicalTrials.gov under the no. NCT04742374 and date of registration 10 December 2020.

Symmetrical isolated globus pallidus infarction due to bilateral carotid artery dissection

A 43-year-old woman presented 1 day after whiplash injury with behavior change, hypersomnia, and abulia. MRI showed symmetrical globus pallidus infarction and bilateral watershed hypoperfusion. Magnetic resonance angiography (MRA) showed bilateral carotid artery dissection. To our knowledge, isolated symmetrical globus pallidus infarction related to bilateral carotid dissection has never been reported earlier.

[Therapeutic plasmapheresis procedures: An alternative to the disruption of the supply of polyvalent immunoglobulin in autoimmune pathologies. Medico-economic study]

INTRODUCTION

The supply of human polyvalent immunoglobulin has been under severe pressure for several years. This has led to a prioritisation of indications and a record increase in the amount of reimbursement without solving the problem of demand. Treatment by therapeutic plasmapheresis appears to be an alternative to be considered for the treatment of certain dysimmune diseseases. To discuss this alternative, we are conducting a medico-economic study comparing the polyvalent immunoglobulin strategy versus different therapeutic plasmapheresis system in the treatment of a chronic dysimmune disease.

POPULATION AND METHOD

The medico-economic study was conducted using the example of a 75 kg patient with chronic polyradiculoneuritis dependent on chronic therapy with a comparison of sequential treatment with one session of therapeutic plasmapheresis versus a course of intravenous polyvalent immunoglobulin. The medico-economic study includes an evaluation from a public health care system perspective complemented by a hospital-based approach that justifies estimating the cost of different therapeutic plasmapheresis systems based on a bottom-up micro-costing approach.

RESULTS

From the point of view of the care system, for information, a 20 g bottle of polyvalent immunoglobulin has a similar cost to a therapeutic plasmapheresis session. In our example, the cost of a maintenance treatment repeated every 2 to 4 weeks in chronic polyradiculoneuritis in a 75 kg patient is 1284.13 euros for a therapeutic plasmapheresis session versus 7331.60 to 9426.84 euros for a 1.5 to 2 mg/kg polyvalent immunoglobulin treatment. Furthermore, from the point of view of the hospital system, the cost of the different TT techniques evaluated varies moderately with the cost depending mainly on the quantity of albumin infused or the medical device used.

CONCLUSION

In the chronic sequential treatment of chronic polyradiculoneuritis, the cost of therapeutic plasmapheresis could be lower than with polyvalent immunoglobulin from a healthcare system perspective. The cost to the health care facility between different therapeutic plasmapheresis techniques differs little. This study provides arguments suggesting that if therapeutic plasmapheresis can be implemented with a dedicated technical platform, it is a serious alternative to be considered without additional costs.