Non-recurrent SEPT9 duplications cause hereditary neuralgic amyotrophy.

BACKGROUND: Genomic copy number variants have been shown to be responsible for multiple genetic diseases. Recently, a duplication in septin 9 (SEPT9) was shown to be causal for hereditary neuralgic amyotrophy (HNA), an episodic peripheral neuropathy with autosomal dominant inheritance. This duplication was identified in 12 pedigrees that all shared a common founder haplotype. METHODS AND RESULTS: Based on array comparative genomic hybridisation, we identified six additional heterogeneous tandem SEPT9 duplications in patients with HNA that did not possess the founder haplotype. Five of these novel duplications are intragenic and result in larger transcript and protein products, as demonstrated through reverse transcription-PCR and western blotting. One duplication spans the entire SEPT9 gene and does not generate aberrant transcripts and proteins. The breakpoints of all the duplications are unique and contain regions of microhomology ranging from 2 to 9 bp in size. The duplicated regions contain a conserved 645 bp exon within SEPT9 in which HNA-linked missense mutations have been previously identified, suggesting that the region encoded by this exon is important to the pathogenesis of HNA. CONCLUSIONS: Together with the previously identified founder duplication, a total of seven heterogeneous SEPT9 duplications have been identified in this study as a causative factor of HNA. These duplications account for one third of the patients in our cohort, suggesting that duplications of various sizes within the SEPT9 gene are a common cause of HNA.

Enteral tube feeding for amyotrophic lateral sclerosis/motor neuron disease.

BACKGROUND: Enteral feeding (tube feeding) is offered to many people with amyotrophic lateral sclerosis/motor neuron disease experiencing difficulty swallowing (dysphagia) and maintaining adequate nutritional intake leading to weight loss. OBJECTIVES: The aim of this review is to examine the efficacy of percutaneous endoscopic gastrostomy placement or other tube feeding placement on: (1) survival; (2) nutritional status; (3) quality of life. Another aim is to examine the minor and major complications of percutaneous endoscopic gastrostomy. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Register (June 2005), MEDLINE (from January 1966 to June 2005), and EMBASE (from January 1980 to June 2005) for randomized controlled trials. In addition we searched MEDLINE (January 1966 to June 2005) and EMBASE (January 1980 to June 2005) to identify non-randomized studies that might be worthy of review and discussion. We checked references in published articles, proceedings of scientific meetings, and enlisted personal communications to identify any additional references. SELECTION CRITERIA: All randomized and quasi-randomized controlled trials were to have been selected. Since no such trials were discovered, all prospective and retrospective controlled studies were reviewed in the 'Background' or 'Discussion' sections of the review. DATA COLLECTION AND ANALYSIS: We independently assessed study methodological design and extracted data. We considered the following outcomes: (1) survival rate in months (of primary interest), (2) nutritional status measured by weight change, change in body mass index, or other quantitative index of nutritional status, and (3) self-perceived quality of life We were also interested in reports of safety of the procedure as indicated by (4) minor and major complications of percutaneous endoscopic gastrostomy or other feeding tube placement. MAIN RESULTS: We found no randomized controlled trials comparing the efficacy of enteral tube feeding with those people who continued to eat orally, without enteral feeding. We summarized the results of retrospective and prospective case controlled studies in the 'Discussion' section of this review. AUTHORS' CONCLUSIONS: There are no randomized controlled trials to indicate whether enteral tube feeding is beneficial compared to continuation of oral feeding for survival. The 'best' evidence to date, based on controlled prospective cohort studies, suggests an advantage for survival in all people with amyotrophic lateral sclerosis/motor neuron disease, but these conclusions are tentative. Evidence for improved nutrition is also incomplete but tentatively favorable. Quality of life has only been addressed by a few researchers and needs more serious attention.

Peripheral neuropathy associated with acquired immunodeficiency syndrome. Prevalence and clinical features from a population-based survey.

We prospectively studied 40 hospitalized patients who had well-established diagnoses of acquired immunodeficiency syndrome. Patients with confounding risk factors for neuropathy were excluded; none of the study patients had known vitamin deficiency, alcoholism, or any metabolic, drug, or toxic factor. Clinical and electrophysiologic evidence of a distal symmetric polyneuropathy was found in 35% (13/37) of the patients. Symptoms and signs of neuropathy were usually mild, and painful dysesthesias were uncommon. Amplitude reduction of sural nerve action potentials distinguished all patients with from those without clinical neuropathy. Results of other electrophysiologic studies of sural, peroneal, and median nerves were typically normal. These results provide evidence of distal axonal degeneration. Neuropathy occurred only in patients with systemic illness longer than five months' duration. When compared with patients without neuropathy, these patients had more severe weight loss and a higher incidence of clinical dementia. Follow-up evaluation showed no evidence of clinical progression over a six-month period. The pathogenesis of this common distal axonal polyneuropathy is unknown and warrants further investigation.

Idiopathic, progressive mononeuropathy in young people.

We describe six young patients with insidiously progressive, painless weakness in the distribution of a single major lower extremity nerve. No cause could be found despite extensive evaluation, including surgical exploration. At the time of diagnosis, all patients had weakness and three patients had sensory loss. In all cases, electromyography revealed a chronic axonal mononeuropathy without conduction block or focal conduction slowing. Magnetic resonance, computed tomographic, and ultrasound imaging studies did not identify a region of nerve swelling, mass, or compression. At surgical exploration, the nerve appeared atrophic in two patients, indurated in one patient, and normal in two patients. Biopsy specimens obtained from two abnormal nerves revealed either wallerian degeneration or endoneurial fibrosis. The clinical features of these patients comprise an unusual clinical entity with no known cause or treatment.

Subacute structural myopathy associated with human immunodeficiency virus infection.

An unusual myopathy characterized by selective loss of thick filaments and widespread formation of rod bodies is described in two men, both seropositive for human immunodeficiency virus. We were unable to find any previous reports documenting this combination of morphological abnormalities, which we believe may be related to human immunodeficiency virus infection. Both patients responded to treatment: one, to steroid therapy; the other, to plasmapheresis.

Electrodiagnostic features of the Guillain-Barré syndrome: the relative sensitivity of different techniques.

We compared the diagnostic sensitivity of somatosensory evoked potentials (SEPs) and F waves with peripheral motor and sensory nerve conduction studies in 15 patients with the Guillain-Barré syndrome. All 4 types of studies were performed on 44 nerves (17 median, 12 ulnar, and 15 lower extremity). In the lower extremities, we used the peroneal nerves for all types of study except peripheral sensory conduction studies, which were performed on the sural nerve. We detected abnormalities by peripheral motor conduction studies in 33 of 44 nerves, by F waves in 31, by SEPs in 23, and by peripheral sensory conduction in 17. The cumulative sensitivity increased with the testing of multiple nerves by motor nerve conduction, sensory nerve conduction, and F-wave studies, but not with multiple SEPs. F-wave studies were significantly more sensitive than SEPs in identifying abnormalities. Thus, the recording of SEPs is indicated for diagnosis of the Guillain-Barré syndrome only if peripheral nerve conduction and F-wave studies are normal.

Longitudinal study of fiber density and motor unit number estimate in patients with amyotrophic lateral sclerosis.

We examined fiber density, compound muscle action potential (CMAP) amplitude, and motor unit number estimate (MUNE) of the abductor digiti minimi and grip strength longitudinally. We sought to determine the effects of ALS on these measurements and to evaluate which of these tests may be more sensitive in evaluating progression of ALS and possibly predicting survival. Ten patients were examined at months 0, 3, and 6. A significant decrease in MUNE and increase in fiber density were observed at months 3 and 6 (p < 0.02) compared with baseline (month 0). Mean CMAP and grip strength declined, but not significantly. The decrease in MUNE over 6 months was significantly greater than that of CMAP and grip strength (p < 0.025). The significant changes in MUNE and fiber density over time suggest that they are more sensitive in measuring the rate of progression of ALS. To evaluate further the utility of these tests, we arbitrarily divided the patients into equal groups based on length of survival. MUNE declined significantly in the group with shorter survival (p < 0.01). Conversely, fiber density increased significantly in patients with longer survival (p < 0.01). With similar statistical analysis there were no significant differences in decline of CMAP or grip strength in either subgroup over 6 months. Our study suggests that MUNE and fiber density are more sensitive than CMAP and grip strength in detecting progression of ALS. Furthermore, we raise the hypotheses that a greater increase in fiber density identifies a group of patients with ALS who will have longer survival, and that a greater decline in MUNE identifies a group with a worse prognosis.

Clinical and electrodiagnostic features of X-linked recessive bulbospinal neuronopathy.

We describe four men from two kinships affected with X-linked recessive bulbospinal neuronopathy, and one sporadic case. All developed postural tremor, weakness, and fasciculations, with onset from age 25 to 39 years. Weakness began in the pelvic girdle or hands, with dysphagia or dysarthria occurring years later in two. Sensory symptoms were present in only one, who also had diabetes mellitus. In contrast, sural nerve action potentials were small or absent in all. Needle EMG showed widespread chronic partial denervation with reinnervation. The characteristic twitching of the chin produced by pursing of the lips consisted of repetitive or grouped motor unit discharges, rather than fasciculations. Broader awareness of the distinctive features of bulbospinal neuronopathy will probably increase the frequency of its recognition. Diagnosis is important for purposes of providing a prognosis for affected men and genetic counseling for affected families.

Sciatic neuropathy: clinical and prognostic features in 73 patients.

We examined the clinical features of patients with sciatic neuropathy and the factors that influence prognosis. Of 92 consecutive patients referred for EMG evaluation of sciatic neuropathy, 73 fulfilled strict inclusion and exclusion criteria and had adequate clinical and electrophysiologic information. The etiologies included hip arthroplasty (21.9%), acute external compression (13.7%), infarction (9.6%), gunshot wound (9.6%), hip fracture/dislocation (9.6%), femur fracture (4.1%), contusion (4.1%), and uncertain (16.4%). We used life table analysis to determine outcome and to identify prognostic factors in patients with acute or subacute onset. Moderate or better recovery (improvement to grade 2 or by two of six clinical grades) occurred in most patients (30% by 1 year, 50% by 2 years, 75% by 3 years). A subgroup experienced excellent improvement (by three of six grades, or to grade 2) less frequently (33% by 2 and 3 years). Of the nine factors tested, two predicted an earlier or better recovery: a recordable compound muscle action potential of the extensor digitorum brevis (p < 0.025), and an initial absence of paralysis of muscles controlling ankle plantar flexion and dorsiflexion (p < 0.05). Thus, good but incomplete recovery occurs over 2 to 3 years in most patients with sciatic neuropathy, particularly in those without severe motor axonal loss.

Botulinum toxin therapy for limb dystonias.

We investigated the effectiveness of botulinum toxin in 17 patients with limb dystonias (10 with occupational cramps, three with idiopathic dystonia unrelated to activity, and two each with post-stroke and parkinsonian dystonia) in a placebo-controlled, blinded study. We identified affected muscles clinically and by recording the EMG from implanted wire electrodes at rest and during performance of tasks that precipitated abnormal postures. There were three injections given with graded doses of toxin (average doses, 5 to 10, 10 to 20, and 20 to 40 units per muscle) and one with placebo, in random order. Subjective improvement occurred after 53% of injections of botulinum toxin, and this was substantial in 24%. Only one patient (7%) improved after placebo injection. Subjective improvement occurred in 82% of patients with at least one dose of toxin, lasting for 1 to 4 months. Response rates were similar between clinical groups. Objective evaluation failed to demonstrate significant improvement following treatment with toxin compared with placebo. The major side effect was transient focal weakness after 53% of injections of toxin.

The role of thermography in the evaluation of lumbosacral radiculopathy.

We studied 27 normal subjects and 30 patients with low back pain to evaluate the diagnostic accuracy of thermography in the diagnosis of lumbosacral radiculopathy. Thermographic abnormality was defined as the presence of either interside temperature difference exceeding 3 standard deviations from the normal mean, or an abnormal heat pattern overlying the lumbosacral spine. In patients with clinically unequivocal radiculopathy, thermography and electrophysiologic study were similar in diagnostic sensitivity, and the 2 methods agreed on the presence or absence of abnormality in 71% of cases. However, the thermographic findings had limited localizing value. Relative limb warming was often seen in patients with acute denervation on EMG, and limb cooling in those with more chronic lesions, but the side of the root lesion could not be identified confidently by thermography alone. Moreover, thermographic abnormalities appeared not to follow a dermatomal distribution and failed to identify the clinical or electrophysiologic level of radiculopathy in most cases. Thus, the thermographic findings are nonspecific, of little diagnostic value, and of uncertain prognostic relevance.

Evaluation of thermography in the diagnosis of selected entrapment neuropathies.

We studied 20 normal subjects, 22 patients with carpal tunnel syndrome, and 15 with ulnar neuropathy at the elbow to compare the diagnostic accuracy of infrared thermography with that of conventional electrodiagnostic studies. We found abnormal thermograms in 55% of patients with carpal tunnel syndrome and 47% with ulnar neuropathy, using 2.5 SD from the normal mean as criteria for abnormality. The abnormalities consisted of either an increase in interside temperature difference in the fingers and hands or an alteration of the normal thenar-hypothenar temperature gradient in the fingers. The sensitivity of thermography was considerably lower than that of conventional electrodiagnostic methods. Moreover, the thermographic abnormalities were nonspecific, and could be misleading as they did not reliably identify the side of lesion or distinguish between median or ulnar nerve involvement. Thus, thermography is not helpful in the diagnosis of these two common entrapment neuropathies.

Relative utility of different electrophysiologic techniques in the evaluation of brachial plexopathies.

We report the results of detailed electrophysiologic studies in 23 patients with suspected brachial plexopathies. In five with neurogenic thoracic outlet syndrome, needle EMG and determination of size of ulnar sensory nerve action potentials (SNAPs) and thenar M waves were important in localizing the lesion; F-response and somatosensory evoked potential (SEP) studies were of more limited utility. All electrodiagnostic studies were normal in 10 patients with nonneurogenic thoracic outlet syndrome. In traumatic (three patients) or idiopathic brachial plexopathy (five patients), needle EMG was especially helpful but, in the former, SEP studies helped to guide management and, in the latter, to confirm the proximal site of the lesion when peripheral SNAPs were normal. The presence of preserved but small SNAPs but absent M waves in patients with traumatic plexopathies suggested a combined pre- and postganglionic lesion.

Neuromuscular effects distant from the site of botulinum neurotoxin injection.

We assessed the severity and temporal profile of distant neuromuscular effects from a single dose (280 units) of botulinum neurotoxin injected into neck muscles for torticollis. We performed single-fiber EMG studies on the biceps brachii of six patients to measure jitter (20 pairs) and fiber density on the initial treatment day and then again, at least once more, after 2 to 12 weeks. No patient developed weakness beyond the neck muscles or decrement of the biceps response to repetitive 3-Hz nerve stimulation. Between the baseline and the last follow-up study, the average of mean MCD increased from 29 microseconds to 38 microseconds (31%). Mean fiber density increased concurrently or earlier from 1.35 to 1.79 (33%). There were no electrophysiologic signs of presynaptic blockade, even at 2 and 4 weeks. The effects we observed are compatible with stimulation of terminal sprouting by the neurotoxin, without significant presynaptic inhibition of acetylcholine release. We therefore believe that higher dosages of the neurotoxin may be used if clinically indicated.

Neurologic complications of lumbar epidural anesthesia and analgesia.

We reviewed the clinical features of 12 patients with neurologic complications following lumbar epidural anesthesia or analgesia. Eleven patients experienced lumbosacral radiculopathy or polyradiculopathy and, of these, 10 received epidural anesthesia or analgesia and one received subarachnoid injection of medication after intended epidural anesthesia. One patient suffered a moderately severe thoracic myelopathy in the setting of unintended spinal anesthesia. The two patients with more severe polyradiculopathy had severe lumbar spinal stenosis on MRI. The other patients experienced mild to moderate neurologic deficits most often involving the L-2 root, and MRIs, when performed, were unremarkable. EMG on three patients helped to localize the lesions to the lumbosacral roots and to quantify the extent of axonal loss. Ten patients were ambulatory upon discharge from the hospital and had good neurologic outcome. One patient with severe polyradiculopathy did not improve after 4 years and had severe motor axonal loss based upon electrodiagnostic studies. The patient with a thoracic myelopathy was ambulatory 4 months after onset. Although generally a safe procedure with low frequency of complications, lumbar epidural anesthesia or analgesia occasionally causes neurologic sequelae such as radiculopathy or myelopathy. Neurologic complications may be more severe in the presence of spinal stenosis or after inadvertent subarachnoid injection of anesthetic or analgesic agent.

Reduced corticomotoneuronal excitatory postsynaptic potentials (EPSPs) with normal Ia afferent EPSPs in amyotrophic lateral sclerosis.

We studied excitatory postsynaptic potentials (EPSPs) arising in single spinal motoneurons (composite EPSPs) induced by Ia afferent and magnetic cortical stimulation in 28 normal subjects ranging in age from 24 to 84 years and 28 patients with amyotrophic lateral sclerosis (ALS) aged 34 to 82 years. The subjects voluntarily recruited single motor units of the first dorsal interosseous muscle. Using peristimulus time histograms, we determined changes in the firing probability of the first dorsal interosseous motor units and measured the magnitude of the EPSP. An early period of increased firing probability (primary peak) occurred at approximately 30 msec after la afferent and 25 msec after cortical stimulation, reflecting underlying EPSPs arising in spinal motoneurons induced by either projection. The latency of the primary peaks for both Ia afferent and cortical stimulation was mildly prolonged in ALS, suggesting a loss of the fastest-conducting spinal motoneurons. Patients with ALS had la afferent-driven EPSPs whose amplitude and rise time were equivalent to those of normal subjects. However, the ratio of cortical to la afferent-driven composite EPSPs in ALS was significantly lower than that for normal subjects. Fourteen of 28 ALS motor units had cortically driven EPSPs that were small or large only because of a prolonged rise time. The findings suggest that in ALS, corticomotoneuronal attrition or dispersion of the descending volley occurs in the presence of normally functioning spinal motoneurons to which they project.

High-titer selective serum anti-beta-tubulin antibodies in chronic inflammatory demyelinating polyneuropathy.

Although chronic inflammatory demyelinating polyneuropathy (CIDP) is presumed to be an autoimmune disorder, no neural antigen has been recognized as an immune target. We found that serum IgM from a patient with CIDP and an IgM paraprotein reacted with a 53-kd protein by Western blot analysis. Amino acid sequence analysis identified this protein as beta-tubulin. We then studied sera from 70 CIDP patients, 35 Guillain-Barré syndrome (GBS) patients, and 483 disease (amyotrophic lateral sclerosis, Alzheimer's disease, multiple sclerosis, diabetes, and other polyneuropathies) and normal controls for selective high-titer anti-beta-tubulin using ELISA methodology. Forty-two percent (30/70) of patients with CIDP had selective high titer IgM reactivity against beta-tubulin; 23% (16/70) had selective high-titer IgG reactivity against beta-tubulin. Overall, 57% of CIDP patients, 20% of GBS patients, and 2% of control patients had selective, high serum IgM or IgG anti-beta-tubulin reactivity. Selective high-titer serum anti-beta-tubulin antibodies occur in a majority of patients with CIDP but are rare in other chronic neuropathies or CNS disorders.

Serum IgM monoclonal autoantibody binding to the 301 to 314 amino acid epitope of beta-tubulin: clinical association with slowly progressive demyelinating polyneuropathy.

We identified five patients with IgM monoclonal autoantibodies that bound to human brain tubulin. In a companion study, we found that IgM in these sera selectively recognized one of three epitopes on tubulin. IgM from three patients bound selectively to a small epitope on human beta-tubulin comprising amino acids 301 to 314. The other two sera recognized tubulin amino acids 215 to 235 and 315 to 336. In this study, we compared the clinical syndromes in these patients with the tubulin epitope recognized by their serum IgM. The three patients with IgM binding to tubulin amino acids 301 to 314 all had chronic inflammatory demyelinating polyneuropathy (CIDP) syndromes with slowly progressive weakness, hyporeflexia, and electrophysiologic studies consistent with demyelination. Two of these patients had significant asymmetry to their weakness. The two other patients had diagnoses of polyradiculopathy and amyotrophic lateral sclerosis with no evidence of peripheral nerve demyelination. We conclude that IgM monoclonal anti-tubulin antibodies have some association with demyelinating polyneuropathy syndromes, but may occur in patients with other clinical syndromes as well. A stronger association with demyelinating polyneuropathies may occur if the anti-tubulin antibodies recognize the 301 to 314 amino acid epitope on tubulin. This tubulin epitope, or a similar one on another molecule, could play an important antigenic role in the development of demyelinating polyneuropathies with features of CIDP.

Peptide T in the treatment of painful distal neuropathy associated with AIDS: results of a placebo-controlled trial. The Peptide T Neuropathy Study Group.

OBJECTIVE: To assess the safety and efficacy of Peptide T in the treatment of painful distal symmetrical polyneuropathy (DSP) associated with human immunodeficiency virus (HIV) infection. BACKGROUND: Painful DSP is a frequent complication of HIV infection, although its etiology and optimal treatment are unknown. Peptide T (D-(alpha 1)-Peptide T-amide) has been found in phase I trials and anecdotal reports to relieve neuropathic pain in AIDS patients. DESIGN/METHODS: In this multicentered, double-blind, randomized study, subjects received intranasal Peptide T 6 mg/day or placebo for 12 weeks. The primary outcome measure was change in the modified Gracely pain score. Secondary efficacy variables were results of neurologic examination, neuropsychological and electrophysiologic studies, global evaluation, and CD4 lymphocyte counts. RESULTS: Of 81 evaluable subjects, 40 received Peptide T and 41 received placebo. The change in pain scores was not significantly different (p = 0.32) in the Peptide T group (-0.24) as compared to placebo (-0.39). Group comparisons were not significantly different for change in any clinical examination or neuropsychologic measure, sural nerve amplitude or conduction velocity, or CD4 lymphocyte count. No significant drug-related adverse effects occurred in either group. CONCLUSION: Intranasal Peptide T is safe but ineffective in the treatment of painful DSP associated with AIDS.

Absence spells. Hyperventilation syndrome as a previously unrecognized cause.

Absence spells in adults have been recognized in association with disorders of excessive somnolence, transient ischemia of the temporal lobes, and seizure disorders. A 66-year-old man who presented with a history of absence spells for more than 20 years is described. After diagnosis of a hyperventilation syndrome without an associated seizure disorder, educational and behavioral therapy without the use of medication has produced a long, continuing remission of these spells. The hyperventilation syndrome continues to present in many ways, often without recognition by physicians for prolonged periods. The case presented exemplifies this problem and may be the first report of absence spells caused by hyperventilation.