Homozygous SMN1 exons 1-6 deletion: pitfalls in genetic counseling and general recommendations for spinal muscular atrophy molecular diagnosis.

We report on a rare homozygous intragenic deletion encompassing exons 1-6 of the SMN1 gene in a patient with spinal muscular atrophy (SMA) born into a consanguineous family. This exceptional configuration induced misinterpretation of the molecular defect involved in this patient, who was first reported as having a classic SMN1 exon 7 deletion. This case points out the possible pitfalls in molecular diagnosis of SMA in affected patients and their relatives: exploration of the SMN1 exon 7 (c.840C/T alleles) may be disturbed by several non-pathological or pathological variants around the SMN1 exon 7. In order to accurately describe the molecular defect in an SMA-affected patient, we propose to apply the Human Genome Variation Society nomenclature. This widely accepted nomenclature would improve the reporting of the molecular defect observed in SMA patients and thus would avoid the commonly used but imprecise terminology "absence of SMN1 exon 7."

[Isolated mandibular B-cell lymphoma revealed by inferior alveolar nerve anesthesia]. / Lymphome B mandibulaire isolé révélé par une anesthésie du nerf alvéolaire inférieur.

INTRODUCTION: Mandibular lymphomas are rare and most often revealed by painless swelling. The authors report the case of a mandibular lymphoma revealed by an isolated lesion of the inferior alveolar nerve evolving for eight months. CASE REPORT: A 41-year-old male patient was followed for left mandibular pain, with progressive hypoesthesia of the left inferior alveolar nerve. The radiological assessments remained normal during eight months. Then a vestibular tumor developed in front of tooth 34. The biopsy revealed a B-cell lymphoma. No other localization was found. The patient was in complete remission two years after polychemotherapy. DISCUSSION: Our observation is unusual in its clinical presentation. Mandibular lymphomas most often present as a painless swelling, sometimes ulcerated in the mouth. They are very rarely diagnosed after an isolated hypoesthesia of V3. Lymphomas are the second most frequent head and neck lymphomas after epidermoid carcinomas, but the frequency seems to be increasing. In almost all the cases, they present as B-cell tumours of the DLBCL subtype in the WHO classification. Mandibular localizations account for only 0.6% of the cases. They are often misdiagnosed as a dental problem. The complete remission rate after chemotherapy ranges from 60 to 80% at one year. Nevertheless, the prognosis remains bad with a survival rate of only 50% at five years.

[Leptomeningeal dissemination after ethmoidal sinus adenocarcinoma surgery: a rare complication]. / Dissémination leptoméningée après chirurgie d'un adénocarcinome de l'ethmoïde.

INTRODUCTION: Although rare, adenocarcinoma is the most frequent neoplasm of the ethmoid sinus and must be regarded as an occupational disease secondary to chronic wood dust exposure. Few cases with neurological metastasis have been reported. CASE REPORT: We report the cases of two patients who developed a multiple cranial nerve disorder for the first case and a cauda equina syndrome for the second, after ethmoid adenocarcinoma surgery. CONCLUSION: Diagnosis of carcinomatous meningitis is difficult and is based on clinical data, CSF analysis and gadolinium-enhanced T1-weighted brain and spinal cord MRI. The implication of surgery is discussed. Prognosis of such a disorder is poor.

[Post-traumatic tarsal tunnel syndrome: interest of muscular MRI]. / Syndrome du canal tarsien post-traumatique : intérêt de l'IRM musculaire.

INTRODUCTION: Tarsal tunnel syndrome is a compressive neuropathy of the tibial nerve with multiple causes. This syndrome is difficult to diagnose and can be missed because of its subjective symptomatology. OBSERVATION: In our patient, suspected post-traumatic tarsal tunnel syndrome was confirmed at MRI. This case highlights muscle signal anomalies caused by their denervation in the tibial nerve territory. CONCLUSION: MRI can provide supplementary information to the electromyography (EMG) and contribute to positive and etiologic diagnosis of peripheral nerve lesions.

[Iris heterochromia in acquired Horner's syndrome]. / Hétérochromie irienne associée à un syndrome de Claude Bernard-Horner acquis.

Horner's syndrome (HS) is related to an interruption of the oculosympathetic nerve pathway. The classic clinical findings associated with this condition are ptosis, miosis, and enophthalmos. Heterochromia is typically described in congenital HS, but it is an uncommon finding in acquired HS. We report a case of post-traumatic HS associated with heterochromia. A literature review indicates that this type of heterochromia may be related to a reduction in the number of iris melanocytes. This mechanism may be the same in the physiological iris color modifications in adulthood.

[Finnish amyloid polyneuropathy in a French patient]. / Une amylose finlandaise chez une patiente française.

INTRODUCTION: Finnish amyloid variety is a rare familial amiloidosis polyneuropathy essentially observed in Finland. It concerns about six hundred people in the world in which five hundred reside in Finland. OBSERVATION: We report a case of a 58-year-old French woman with a 10-year history of lattice cornea dystrophy. She consulted in January 2004 for impaired swallowing, facial paralysis principally of the right superior territory and symptoms of arthritis which had developed a few months earlier. Observation revealed facial cutis laxa, tongue amyotrophy and some fasciculation. Electroneuromyography showed chronic neurogenic involvement of the facial muscles. Limbs and the sympathetic neuronal system were free of involvement. Pathological examination revealed areas of peri vascular amiloid deposits. Molecular biology confirmed the diagnosis of Finnish amiloidosis: substitution of aspartic acid by tyrosine in the 187 codon in the 9th chromosome (gelsoline gene). This mutation has been previously found in Denmark and the Czech Republic. CONCLUSION: Finnish amiloidosis is a familial polyneuropathy characterized by an association of cornea lattice dystrophy, cutis laxa and a chronic neurogenic involvement of the cranial nerves. Two mutations are known. Life expectancy is not affected, but quality of life is altered.

[Chronic inflammatory demyelinating polyradiculoneuropathy: diagnostic strategy. Guidelines of the French CIDP study group]. / Polyradiculonévrites inflammatoires démyélinisantes chroniques: stratégie diagnostique. Recommandations du groupe d'Etude français des PIDC.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) comprises a group of dysimmune neuropathies easily diagnosed in more than half of the patients. Diagnosis is based on clinical, electrophysiological and biological clues. In some patients, diagnosis is unclear because of the debated value of the available clues. In such circumstances, dysimmune neuropathies may not be diagnosed, leading to insufficient treatment. This is an important category of patients because immunomodulatory drugs have proven efficacy. The CIDP spectrum includes a relatively wide range of diseases. Besides the easily recognized classic forms, there are many clinical variants, sometimes with a paucisymptomatic presentation leading to uncertain diagnosis. The French CIDP study group has established guidelines for diagnostic strategy in CIDP patients. The first part of this paper is devoted to the clinical aspects of the disease, classical forms and variants. In the second part, the results of electrophysiological studies are reported. In a third chapter, complementary examinations useful for diagnosis are discussed. The fourth chapter deals with the diagnostic strategy, discussed in relation to the different situations which may be encountered in clinical practice. details the technical modalities of appropriate electrophysiological studies and presents normal results together with those indicating demyelinating neuropathy. Nerve biopsy technique and results are given in appendix II.

[Strategies to interpret late waves in routine neurophysiology]. / Stratégies d'interprétation des ondes tardives en neurophysiologie de routine.

A number of late waves other than F and H spinal waves are commonly observed during motor nerve conduction studies. Simple criteria are available that allow an understanding of their origin and significance. A late wave can be characterized by 1) its origin, proximal or distal to the stimulator, 2) its position with reference to the spinal waves, 3) its latency, stable or not, 4) its appearance in response to all (constant) or not to all stimuli (inconstant), 5) its persistence or not to intense stimuli, 6) its relative threshold, 7) its behavior to paired stimuli (namely if it is or not evoked twice by paired stimuli). By use of these criteria, one may distinguish the late waves that are evoked proximal to the stimulator (indirect late waves), such as the spinal responses (H and F), the motor axon reflex and the indirect double discharge, from those late waves that originate distally to the stimulator (direct late waves) such as the late potential, the myo-axonal ephaptic response and the direct double discharge. Signification of these late waves in relation to peripheral nerve disorders is discussed. Late potentials, motor axon reflex and ephaptic myo-axonal responses are signs of a prior axonal lesions, whereas indirect double discharges relate to an ongoing demyelinating process.

[Neuropathy versus neuronopathy: distinctive features]. / Comment distinguer une neuropathie d'une neuronopathie?

Neuropathy may be difficult to distinguish from neuronopathy, on both motor and sensory sides. A number of disorders that present with characteristic electro-clinical features are readily recognized. Except for those, distinction of the lesions that concern the peripheral nerve cell or the axon may require support of clinical, electrophysiological and other ancillary tests. Distinction between motor neuropathy and neuronopathy can be based on the abnormalities of nerve conduction and on the signs that relate to the reinnervation process. Signs of terminal axonal reinnervation, such as motor axon reflex, may be observed in axonal neuronopathies, whereas only collateral reinnervation occurs in motor neuronopathies. Sensory axonopathies are usually characterized by clinical and electrophysiological findings that are axon length-dependent, by the course of the disorder that is most often chronic, and by possible reversibility. Sensory neuronopathies are usually subacute and induce clinical deficits that are more or less widespread to the whole body surface rather than distal. Follow-up studies disclose limited or absent recovery. A better knowledge of the structural differences of motor and sensory neurons and axons will improve our understanding and lead to the development of specific tests. Meanwhile, although some parameters and techniques should still be improved, electrophysiological and additional tests are useful to detect and to distinguish the peripheral nerve disorders that affect the nerve cell bodies and their axons.

Exercise test in muscle channelopathies and other muscle disorders.

We studied the percentage change in compound muscle action potential (CMAP) amplitude and area during and after a 5-min maximal contraction of the muscle. The exercise test (ET) was performed on 64 patients with different muscle disorders and on 46 normal controls. The range of normal ET values was defined as the mean + 2 SD of the control values. The mean sensitivity of the test was 63% in the whole group with ion channel muscle disorders, the highest sensitivity being seen in primary periodic paralysis (81%) and the lowest in chloride channelopathies (17%). In thyrotoxic periodic paralysis, the ET was abnormal in the three of the four patients studied. In patients with myotonic dystrophy, a smaller than normal increase in CMAP amplitude occurred during and after exercise, whereas in proximal myotonic myopathy a normal initial increase in CMAP amplitude was followed by an abnormal decrement. We conclude that the ET can be of use in confirming abnormal muscle membrane excitability in patients with calcium and sodium channelopathies and thyrotoxic periodic paralysis. In chloride channelopathy, the test may also be abnormal, but shows no, or only a small, increase in amplitude or area in the immediate postexercise period. The test may also be abnormal in proximal myotonic myopathy, but is normal in myotonic dystrophy.

High frequency discharge of a fraction (f) of motor unit action potential.

Two repetitive discharges, firing at 105 and 180 Hz, were evoked in muscles with chronic denervation. They were delayed following a motor unit action potential (M), and their maximum duration was 800 and 50 ms, respectively. The potential of both high frequency discharges was of low amplitude and short duration. It was considered to be a fraction (f) of the motor unit potential, and to depend on muscle fibres re-innervated by an axonal branch. The repetitive mechanism was tested by double stimulation. It seemed to be an ephaptic re-excitation of the axonal branch by a sprout rather than an ectopic trigger locus on the latter. The antidromic waves, associated with the repetitive discharges on the axonal branch, failed to be transmitted to the main axon. This failure, assimilated to a conduction block, was complete in the first case as M was not repetitive. It was intermittent in the second case as M was firing intermittently. Repetitive activity associated with 'terminal multifocal block' could be relevant to the fractional activation observed by others in some disease states.

Cancellation of single F wave by double stimulation in case of chronic denervation.

Single F waves evoked by stimulation with above threshold intensity are cancelled by a second shock, as was previously demonstrated with maximal or sub-maximal intensity. Double stimulation of any intensity thus makes it possible to detect a possible reflex component in the spinal response, by elimination of the F wave. As an H or a heteronymous H reflex may be a sign of a disordered central motor system state, this fast method has a direct clinical utility.

[Value of gadolinium magnetic resonance imaging of the lumbosacral roots in acute polyradiculoneuritis]. / Intérêt de l'imagerie en résonance magnétique avec gadolinium des racines lombo-sacrées dans les polyradiculonévrites aiguës.

Four patients with acute inflammatory polyradiculoneuropathy were evaluated with MRI. In 3 of 4 cases, gadolinium enhancement was observed in the nerve roots of cauda equina, on frontal and horizontal slices. This enhancement was correlated with the severity of the clinical picture and the cerebrospinal-fluid inflammatory protein concentration and supports the inflammatory nature of this forms of acute polyradiculoneuropathy.

Early seizures after acute stroke: a study of 1,640 cases.

We evaluated prospectively the occurrence of seizures within 15 days of a first stroke or transient ischemic episode in 1,640 patients to study relation between seizures and type of stroke. Seizures occurred in 90 patients (5.4%), including 36 (4.4%) of 814 with infarct owing to atheroma, 21 (16.6%) of 126 with infarct owing to cardiogenic embolus, 3 (1%) of 273 owing to lacunar infarct, 5 (1.9%) of 259 owing to transient ischemic attack (TIA), 21 (16.2%) of 129 owing to supratentorial hematoma, and 4 (16.6%) of 24 owing to subarachnoid hemorrhage. Thirteen (14.6%) of 89 subcortical infarcts were associated with seizures. Seizures were the initial sign of stroke in 80 (89%) of 90 cases and were usually single and partial. Seizure symptoms were most often motor, sensory, or visual.

[Gyratory epileptic seizures. Radioclinical correlations]. / Les crises épileptiques giratoires. Corrélations radio-cliniques.

The authors report 3 cases of gyratory seizures whose epileptic nature was demonstrated on the following features. They appeared with a loss of consciousness. In 2 cases, they ended with a tonic-clonic generalized fit and in the 3 cases, they were mixed with other generalized seizures. From an etiological point of view, in 2 cases, a deep lesion was discovered, the first one near the paracentral lobule, the second in the para-thalamic area. The third one was an idiopathic generalized epilepsy on clinical and electroencephalographic grounds. These 3 cases focus on the difficulties to classify gyratory seizures that may appear in 2 opposite situations, namely in symptomatic partial epilepsy and in idiopathic generalized epilepsy.

[Investigation via electroencephalogram with sphenoidal electrodes of a case of reading epilepsy: role of the temporal lobe in the emotional evocation of seizures]. / Exploration d'un cas d'épilepsie à la lecture par EEG avec électrodes sphénoïdales: rôle des régions temporales dans le déclenchement émotionnel des crises.

Reading epilepsy in a 20-year-old male. Electroencephalographic study with sphenoidal electrodes localized the onset of critical spikes in the temporal areas (especially the left). The frequency and diffusion of critical spikes were increased when material read had an emotional content. This case report supports the "communication" hypothesis as opposed to hypotheses that emphasize proprioceptive and other "lower order" stimuli in evoking seizures while reading. The authors discuss the role of the temporal lobe in reading: lexical function, treatment of visual information and emotional integration of stimuli.

[Electrophysiologic data on myasthenic syndromes of the Lambert-Eaton type. A series of 23 cases]. / Données électrophysiologiques dans les syndromes myasthéniformes de type Lambert-Eaton. A propos d'une série de 23 cas.

The electrophysiological data of 23 adult patients with Lambert-Eaton myasthenic syndrome (LEMS) have been reviewed. Lung carcinoma was disclosed in 17. In six cases with an EMG follow-up ranging between one and 17 years no carcinoma was detected. The results of repetitive nerve stimulation test (RNS) were not statistically different between the 2 groups. Low CMAP ulnar amplitude was present in all patients (mean: 1.7 mV). Decremental response at low rate of stimulation (3 Hz) was present in 17/20 (means: 30%). An abnormal incremental response at high rate of stimulation was present in all cases (mean: 826%). The authors emphasize the interest of a 50 Hz stimulation for 4 s. Increase of the 'F-wave' amplitude was noticed in some cases. Electrophysiological changes suggestive of an associated mild neuropathy were noticed in eight patients but H-reflex was present in 3/3 cases. SFEMG abnormalities were found in 6/6 cases. In one case, stimulated SFEMG showed more blockings and an increased jitter with low rate of stimulation. In one case the electrical pattern of RNS could be misinterpreted as myasthenia gravis in one tested muscle only. The author's results suggest that CMAP amplitude and RNS test could be used to appreciate the short-term improvement of LEMS with treatment and in some cases for the long-term follow-up.

[EEG periodic lateralized activities associated with ischemic cerebro-vascular strokes: physiopathologic significance and localizing value]. / Activités EEG périodiques latéralisées au cours des accidents vasculaires cérébraux ischémiques: signification physiopathologique et valeur localisatrice.

Eleven cases of periodic lateralized epileptiform discharges (PLED) with stroke (9 cases) or transient ischemic attacks are reported. PLEDs are often associated with depression of conscience (81%) or partial pure motor epileptic seizures (90%). PLEDs and seizures seem independent on EEG. Ischemic strokes associated with PLEDs have some characteristic features: old age, vascular risk factors, parieto-occipital areas infarcts and frequent association with TIAs. PLEDs seem to be often associated with watershed infarcts. The relations between PLEDs and cerebral ischemia are discussed.

[Electrophysiologic investigation of the anterior temporal and frontal lobes: sphenoidal and intraorbital electrodes]. / L'exploration électrophysiologique de la face basale du lobe temporal et du lobe frontal: intérêt des électrodes sphénoïdales et intraorbitaires.

The authors have evaluated the interest of sphenoidal electrodes in detection of internal temporal spikes, and intra-orbital electrodes in the detection of orbito-frontal spikes. From a study of 26 patients, 21 with sphenoidal electrodes, 3 with intra-orbital electrodes and 2 with both electrodes, they observed the sensitivity and specificity of such electrodes in detecting spikes with no traduction upon extra-cranial electrodes, or with an unsuspected traduction as spikes at a distance from deep electrodes, or spikes on 2 foci, or bisynchronous discharges. Sphenoidal and intra-oribital electrodes constitute a non-invasive method that provides excellent information in the exploration of the mesiobasal cerebral face. Indications for the use of such a method are complex absences without EEG traduction or with an unsuspected traduction and without abnormalities on CT scan, in the context of functional surgery of epilepsy.

[Identification of temporal epileptic seizures using percutaneous sphenoidal electrodes]. / Identification des crises épileptiques temporales à l'aide d'électrodes sphénoïdales percutanées.

The authors have evaluated the indications, methods and results of sphenoidal electrodes in epilepsy. This method makes it possible to study the hippocampal area which cannot be studied by extracranial electrodes. It also localizes in a temporal lobe complex seizures without electrical events, or complex seizures giving bilateral temporal spikes or a fronto-temporal focus of spikes. It may even show evidence of temporal focus in cases with bilateral and synchronous spikes. Thus, sphenoidal electrodes enable temporal seizures to be identified and localized, leading to more specific neuroradiological explorations and therefore helping in the selection of patients for specific surgery.