[Neuropathies associated with paraproteinemia (monoclonal gammopathy)]. / Neuropathies associées aux paraprotéinémies (gammapathies monoclonales).

Coexistence of neuropathy and paraproteinemia (monoclonal gammopathy) is a common and complex problem seen in clinical practice and requires the distinction of specific syndromes. The clinical courses of these neuropathies are typically chronic and progressive. A precise distinction of the type of haematologic disorder associated (benign or malignant), investigation of other organs manifestations, and assessment of specific markers are mandatory. These steps are important to initiate an appropriate therapy that may include chemotherapy and/or immunosuppressive treatment targeting the neuropathy and the haematological dysfunction.

[2011: What's new in dysimmune neuropathies]. / Revue de la littérature 2011: neuropathies dysimmunitaires.

There are strong research activities in the field of dysimmune neuropathies. In Guillain-Barré syndrome, new pathophysiological mechanisms have been demonstrated with the potential development of new therapies, a clinical prediction model is applicable early in the course of disease, and under investigation are new treatment strategies with adapted intravenous Ig dosages. In chronic inflammatory demyelinating polyneuropathies, current diagnostic tests are discussed but biomarkers are needed, such as histological changes or differential gene expression in nerve or skin biopsies. The exploration of novel therapeutic approaches including monoclonal antibodies and oral immunosuppressants, known from multiple sclerosis studies, suggests new approaches to treatment. Changes of the peripheral nerves on MR imaging are better known and the usefulness of serum antibodies is reviewed.

[Ganglionopathies: evolving concept and ideas on management]. / Ganglionopathies: évolution du concept et prise en charge.

Sensory ganglionopathies have a frequent association with neoplastic disorders (paraneoplastic subacute sensory neuronopathy, or SSN) or dysimmune disorders, with drugs, such as cisplatin or pyridoxine, and with inherited disorders with degeneration of dorsal root ganglion cells. Unsteady gait and pseudoathetoid movements of the hand are the distinctive signs encountered in these disorders. The chronic disorders are characterized by non-length-dependent abnormalities of sensory nerve action potentials (SNAPs) and differ from other sensory neuropathies in showing a global, rather than distal, decrease in SNAP amplitudes. This review focuses on recent advances in defining the mechanisms involved in sensory ganglionopathies, and describes the differential diagnosis including the rarely encountered hereditary neuronopathies and the infectious causes.

Favourable outcome of progressive multifocal leucoencephalopathy in two patients with dermatomyositis.

Progressive multifocal leucoencephalopathy (PML), a demyelinating disease caused by the JC virus (JCV), occurs in immunosuppressed patients and carries a poor prognosis. A favourable outcome is reported in two patients with PML and dermatomyositis. Immunosuppressive drugs were stopped in patient 1 but could only be partially tapered in patient 2. The JCV-specific CD8+ T cell response was strong in patient 1 and weak in patient 2. Both were treated with cytosine-arabinoside, and patient 2 was also treated with mirtazapine, a 5HT2A receptor antagonist. Combination of these drugs might be helpful to treat HIV-negative patients with PML.

Improved sciatic nerve regeneration by local thyroid hormone treatment in adult rat is accompanied by increased expression of SCG10.

Thyroid hormone plays an important role in regulating the development and regeneration of the nervous system. Our previous work showed that local administration of triiodothyronine (T3) at the level of transected rat sciatic nerve increased the number and diameter of regenerated axons, but the mechanism underlying the improved regeneration is still unclear. Here, we have investigated the effect of T3 on the expression of SCG10, a regulator of microtubule dynamics in growth cones. After transection of adult rat sciatic nerves, silicone tubes were implanted and filled with T3 or phosphate-buffered solution. At various time points following surgery, the expression of SCG10 protein and mRNA was analyzed. Semi-quantitative Western blot analysis revealed that sciatic nerve transection induced a more than 20-fold upregulation of SCG10 protein in proximal nerve segments at 1 day post-lesion, while at this time point, SCG10 mRNA in dorsal root ganglion neurons was not increased yet. The increase in SCG10 protein and mRNA could be observed over 30 days. Local T3 treatment significantly enhanced the increase in SCG10 protein levels about two-fold in the different segments of transected nerve during the regeneration period. Also SCG10 mRNA levels in lumbar ganglia were enhanced. Immunohistochemical analysis showed that T3 treatment not only increased the number of SCG10 positive axons but also the intensity of their staining. These results suggest that SCG10 is involved in the regulation of regeneration. The stimulating effect of T3 on SCG10 expression could provide a mechanism by which T3 enhances peripheral nerve regeneration.

[Mutation of the aprataxin gene presenting with Charcot-Marie-Tooth-like neuropathy and cerebellar ataxia]. / Amyotrophie de type Charcot-Marie-Tooth associée à une ataxie cérébelleuse autosomique récessive révélatrice d'une mutation du gène de l'aprataxine.

BACKGROUND: Phenotype-genotype correlations, generally based on predominant associated signs, are being increasingly used to distinguish different types of autosomal recessive cerebellar ataxias (ARCA). CASE REPORTS: Two brothers developed signs of cerebellar ataxia with peripheral axonal motor and sensory neuropathy, distal muscular atrophy, pes cavus and steppage gait as seen in Charcot-Marie-Tooth neuropathy. The examination also showed oculomotor apraxia. Sural nerve biopsy revealed conspicuous reduction in the density of myelinated fibres but preservation of unmyelinated nerve fibres. Blood tests revealed low serum albumin and elevated cholesterol. A homozygous W279X truncating mutation was identified in exon 6 of the APTX gene, confirming the diagnosis of cerebellar ataxia with oculomotor apraxia type 1 (AOA1). CONCLUSIONS: These cases illustrate the presentation of AOA1 type of ARCA and discuss the role of peripheral neuropathy in the differential diagnostic of the ARCAs variants.

[Neurological manifestations of IgM dysglobulinemia]. / Dysglobulinémies IgM et complications neurologiques.

Disturbancies in neurological functions associated with paraproteinaemic states are well documented. In recent years increasing attention has been given to paraproteinemia in the absence of evidence of malignancy. In this article we review the main clinical and pathological features associated with IgM paraproteins. Neurological complications affecting the central nervous system are rare, while peripheral neuropathies are frequently observed. Recent advances at the histological and molecular level have allowed a better characterization of clinical syndromes and have given new insights into their pathogenesis. The most convincing evidence for a causal relationship can be drawn from IgM monoclonal gammopathies with specificities directed against carbohydrate determinants of the myelin associated glycoprotein (MAG). There remain, however, many unresolved questions such as how monoclonal anti-MAG IgM antibodies cross the blood-nerve barrier and trigger a chronic demyelinating polyneuropathy while the central nervous system is essentially spared. Current immune therapies for neuropathy associated with IgM paraproteins are temporarily effective in half of patients and are often associated with considerable side effects which limit their prolonged use and efficacy. The availability of safer therapies such as humanized monoclonal antibodies that eliminate specifically B-cell and B-cell precursors may open a new avenue for the management of these patients.

[Carpal tunnel syndrome with an unusual cause: a malignant nerve sheath tumor of the median nerve]. / Syndrome du canal carpien de cause rare: une tumeur maligne des gaines nerveuses du nerf médian.

We report on the follow-up of a patient who developed symptoms suggestive of carpal tunnel syndrome. Symptoms were however atypical with involvement of the nondominant hand and with selective, fascicular, electroneurographic changes. During the surgical decompression of the median nerve at the wrist a tumor was found, corresponding to an isolated malignant peripheral nerve sheath tumor (MPNST) of mild type. A course of local radiation therapy was completed, with no sign of recurrence, and a normalization of the serum level of neurone specific enolase.

Clinicopathological and molecular biological studies in a patient with neurolymphomatosis.

We describe a patient with a clinical disorder that resembled vasculitic neuropathy in which peripheral nerves were successively affected over several months, but without systemic involvement. An initial muscle biopsy near the involved nerves showed signs of nonspecific inflammation around the muscle and nerve fibers. Immunosuppressive treatment resulted in a dramatic reduction in pain, but relapses of the disease eventually occurred, and the patient died 22 months after onset of the first symptoms. Pathologically, a malignant non-Hodgkin's B-cell lymphoma, restricted to the intra- and extradural peripheral nervous system, was found. The demonstration by Southern blotting of immunoglobulin heavy chain gene rearrangement confirmed the monoclonal nature of the lymphomatous cells. In situ hybridization tests for Epstein-Barr and herpes virus subtypes were negative. Our case underlines i) how difficult diagnosis can be despite extensive investigations, ii) the usefulness of immunosuppressive treatment in the early stage of the disease, iii) the importance of immunostaining and genome analysis for distinguishing between different types of human neurolymphomatosis, and iv) the fact that the initial inflammatory process in the muscle biopsy may be interpreted either as a paraneoplastic effect of the lymphoma or as a viral inflammatory neuromyopathy that triggers the development of the malignant lymphoma.

The mutation of Pro789 to Leu reduces the activity of the fast-twitch skeletal muscle sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA1) and is associated with Brody disease.

Brody disease is a rare inherited disorder of fast-twitch skeletal muscle function and is characterized by a lifelong history of exercise-induced impairment of skeletal muscle relaxation, stiffness, and cramps. The autosomal recessive inheritance of mutations in ATP2A1, the gene encoding SERCA1, which is the fast-twitch skeletal muscle sarcoplasmic reticulum Ca2+ ATPase, has been associated with Brody disease in three of six Brody families in which ATP2A1 has been sequenced. In the present analysis of the ATP2A1 gene in four unrelated families with autosomal recessive inheritance of Brody disease, three mutations were found in two families, leading to premature stop codons and truncated SERCA1. In a third family, the homozygous substitution of T for C2366 led to the missense mutation of Pro789 to Leu. The Pro789 to Leu mutant was readily expressed in HEK-293 cells, but it demonstrated an almost complete loss of Ca2+ transport activity because of reduced Ca2+ affinity. In a fourth family, the heterozygous substitution of T for C2455, mutating Arg819 to Cys, was identified. This mutation was also readily expressed in HEK-293 cells and shown to have near normal Ca2+ transport activity, indicating that it is not causal for Brody disease. These results confirm the genetic heterogeneity of Brody disease and emphasize the importance of a functional test for mutant SERCA1; immunostaining of skeletal muscle to detect the loss of SERCA1a protein is not adequate for the diagnosis of ATP2A1-linked Brody disease.

Genetic, cytogenetic and physical refinement of the autosomal recessive CMT linked to 5q31-q33: exclusion of candidate genes including EGR1.

Charcot-Marie-Tooth disease is an heterogeneous group of inherited peripheral motor and sensory neuropathies with several modes of inheritance: autosomal dominant, X-linked and autosomal recessive. By homozygosity mapping, we have identified, in the 5q23-q33 region, a third locus responsible for an autosomal recessive form of demyelinating CMT. Haplotype reconstruction and determination of the minimal region of homozygosity restricted the candidate region to a 4 cM interval. A physical map of the candidate region was established by screening YACs for microsatellites used for genetic analysis. Combined genetic, cytogenetic and physical mapping restricted the locus to a less than 2 Mb interval on chromosome 5q32. Seventeen consanguineous families with demyelinating ARCMT of various origins were screened for linkage to 5q31-q33. Three of these seventeen families are probably linked to this locus, indicating that the 5q locus accounts for about 20% of demyelinating ARCMT. Several candidate genes in the region were excluded by their position on the contig and/or by sequence analysis. The most obvious candidate gene, EGR1, expressed specifically in Schwann cells, mapped outside of the candidate region and no base changes were detected in two families by sequencing of the entire coding sequence.

[Facial myositis: a localized form of generalized myositis?]. / Myosite faciale: une forme localisée de myosite généralisée?

We report a case of myositis presenting as an apparently unique progressive facial weakness. The only biological abnormality after an 8-year follow-up was an immunocytoma. Molecular analyses excluded facioscapulohumeral muscular dystrophy. Based on this single case and a review of the literature, we suggest a continuum between focal myositis and generalized myositis.

Familial cardiomyopathy and distal myopathy with abnormal desmin accumulation and migration.

Desminopathies form a heterogeneous group of myopathies characterised by pathological aggregations of desmin. We report a family, where mother and daughter presented with an atrioventricular block and a slowly progressive distal muscular weakness, with non-homogeneous focal atrophy on computed tomography scans. The mother developed a severe global heart insufficiency necessitating a heart transplantation at 56 years of age. Skeletal muscle biopsies were characterised by inclusion bodies strongly expressing desmin and alpha B-crystallin, with a predominantly subsarcolemmal localisation. Ultrastructurally most inclusions corresponded to non-membrane bound granulo-filamentous material with disruption of myofibrils. An immunoblot showed a hyperintense desmin band at 53 kDa and a second band at 49 kDa, the latter being absent in controls. The cardiac muscle of the explanted heart showed very similar inclusions. These cases illustrate that in this distinct subtype of desminopathies the cardiac muscle alterations are comparable with those observed in skeletal muscle, and suggest the possibility of a primary desmin pathology.

Stress urinary incontinence due to a low-pressure urethra: a socially invalidizing disease.

To compare the quality of life and clinical findings of patients with low-pressure urethra (LPU: < or = 20 cm H2O) with those of stress urinary incontinent (SUI) patients without LPU, and to compare the quality of urethral sphincter (US) muscle innervation parameters in LPU patients with those in control continent patients. Historical, clinical, urodynamic, and US muscle innervation parameters were compared in 38 LPU (group 1), 241 SUI (group 2), and 7 control patients (group 3). In comparison with group 2, the incidence of previous surgery and daily incontinence episodes, SUI severity, and pad test values were significantly higher in group 1, whereas the incidence of previous traumatic deliveries was the same in both groups. The mobility of the bladder neck assessed by the Q-Tip test was significantly reduced in group 1. In comparison with group 3, US motor unit potential (MUP) duration and pudendal motor latencies to the urethral sphincter (PMLUS) were increased in LPU group 1 patients, whereas there was no difference in these parameters between LPU patients with or without previous incontinence surgery. Fifty-three percent of our LPU patients had normal PMLUS, but showed signs of abnormal reinnervation on quantitative electromyography. Three nullipara LPU patients had normal MUP durations and PMLUS values, but a decreased area in response to pudendal nerve stimulation. Apart from a rare form of LPU in nullipara patients, probably due to a dysgenesis of their US muscle, LPU patients suffer from neuro-muscular damage responsible for a severe urinary invalidity. Previous incontinence surgery, as well as previous vaginal deliveries, may be responsible for such US damage.

[Myasthenia-like syndromes: current and future treatments]. / Syndromes myasthéniformes: traitements actuels et futurs.

Therapeutical aspects of disorders of the neuromuscular transmission are based on differential diagnosis between pre- or post-synaptically localized abnormalities of the neuromuscular junction, recognition of acquired and congenital forms and search for associated diseases and tumors, on prescription of drugs improving the transmission of acetylcholine and immunosuppressive agents, and on regular and quantified follow-up. In this clinical and therapeutic review, the two most common forms, myasthenia gravis and the Lambert-Eaton myasthenic syndrome, are discussed in the light of the 44 patients recently seen in our department.

Chronic relapsing neuropathy associated with Castleman's disease (angiofollicular lymph node hyperplasia).

We report a 17-year-old patient who presented a chronic relapsing sensorimotor demyelinating neuropathy with 6 relapses over a 7-year period, preceding by 4 years the diagnosis of a multicentric angiofollicular lymph node hyperplasia. A role for Epstein-Barr virus (EBV) as a trigger of the neuropathy may be suggested by the presence of EBV DNA in the biopsied abdominal abdominal adenopathies. This unusual reported association seems to have a better prognosis than the known chronic progressive form of neuropathy associated with Castleman's disease and the Crow-Fukase syndrome.