Mónica Povedano

Diagnosis of Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth (CMT) disease or hereditary motor and sensory neuropathy (HMSN) is a genetically heterogeneous group of conditions that affect the peripheral nervous system. The disease is characterized by degeneration or abnormal development of peripheral nerves and exhibits a range of patterns of genetic transmission. In the majority of cases, CMT first appears in infancy, and its manifestations include clumsiness of gait, predominantly distal muscular atrophy of the limbs, and deformity of the feet in the form of foot drop. It can be classified according to the pattern of transmission (autosomal dominant, autosomal recessive, or X linked), according to electrophysiological findings (demyelinating or axonal), or according to the causative mutant gene. The classification of CMT is complex and undergoes constant revision as new genes and mutations are discovered. In this paper, we review the most efficient diagnostic algorithms for the molecular diagnosis of CMT, which are based on clinical and electrophysiological data.

Analysis of the CHCHD10 gene in patients with frontotemporal dementia and amyotrophic lateral sclerosis from Spain

Sir, Recently, a study identified a mutation (c.176C>T, p.S59L) in the CHCHD10 gene as a cause of amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD) in a large pedigree with mixed phenotypes encompassing ALS, FTD, cerebellar ataxia and mitochondrial myopathy (Bannwarth et al. , 2014).The same mutation was also found in a second kindred suffering from ALS, FTD and/or parkinsonian signs by the same authors. Additional mutations (p.R15L, p.P34S, p.G66V and p.P80L) have been subsequently reported in ALS and FTD with motor neuron disease (FTD-MND) patients (Chaussenot et al. , 2014; Johnson et al. , 2014; Muller et al. , 2014; Kurzwelly et al. , 2015; Ronchi et al. 2015; Chio et al. , 2015). More recently, exon 2 of the CHCHD10 gene has been sequenced in a cohort of ALS, FTD, Parkinsons disease and Alzheimer’s dementia, revealing two novel mutations (p.P23T and p.A35D) in two patients with FTD (Zhang et al. , 2015). Importantly, some of these screenings have not included neurologically healthy individuals from the same geographic origin (Bannwarth et al. , 2014; Johnson et al. , 2014; Muller et al. , 2014; Kurzwelly et al. , 2015) and therefore, the real allele diversity within CHCHD10 might have been missed. This could have important consequences in terms of establishing firm …

Very early electrodiagnostic findings in Guillain-Barré syndrome

Electrodiagnostic studies play a key role in the evaluation of patients with Guillain‐Barré syndrome (GBS). However, at early stages patients may not meet current neurophysiologic criteria. We report electrodiagnostic findings for 18 patients with suspected GBS within 4 days of clinical onset. Fifteen patients (83%) showed abnormality in the motor nerve conduction study. Prolonged distal motor latency (DML) was the most frequent demyelinating parameter (seen in 55% of patients). Abnormal late responses were noted in 14 patients (77%). Electrodiagnostic study of cranial nerves was abnormal in eight (44%), and motor nerve conduction velocity was abnormal in only six patients (23%). The study shows a predominant motor neuropathy pattern followed by a sural‐sparing pattern; no patients showed a strictly normal electrodiagnostic study. Reduced distal compound muscle action potential and prolonged DML in the demyelinating range were associated with severity of GBS on admission. After the electrodiagnostic study, 5 patients (27%) already fulfilled electrodiagnostic criteria for acute inflammatory demyelinating polyneuropathy (AIDP), 1 (5%) for the axonal variant of GBS, and 13 (72%) were classified as equivocal. We conclude that exhaustive electrodiagnostic studies of patients with suspected GBS in very early stages are useful in the diagnosis and management of the condition.

Electrophysiological study of ephaptic axono-axonal responses in hemifacial spasm

One of the classic features of hemifacial spasm (HFS) is spread of the blink reflex responses to muscles other than the orbicularis oculi. The pathophysiological mechanisms underlying the generation of such abnormal responses include lateral spread of activity between neighboring fibers of the facial nerve and hyperexcitability of facial motoneurons. In this report we present evidence for another mechanism that can contribute to the generation of responses in lower facial muscles resembling the R1 response of the blink reflex. In 13 HFS patients, we studied the responses induced in orbicularis oris by electrical stimuli applied at various sites between the supraorbital and zygomatic areas. We identified responses with two different components: an early and very stable component, with an onset latency ranging from 10.5 to 14.8 ms, and a more irregular longer‐latency component. Displacement of the stimulation site away from the supraorbital nerve and towards the extracranial origin of the facial nerve caused a progressive shortening of response latency. These features indicate that, in our patients, the shortest latency component of the orbicularis oris response was likely generated by antidromic conduction in facial nerve motor axons followed by axono‐axonal activation of the fibers innervating the lower facial muscles. Our results suggest that motor axono‐axonal responses are generated by stimulation of facial nerve terminals in HFS. Muscle Nerve, 2006

Sera from amyotrophic lateral sclerosis patients induce the non-canonical activation of NMDA receptors “in vitro”

Amyotrophic lateral sclerosis (ALS) is a neuromuscular disease characterized by the selective loss of both upper and lower motoneurons (MNs). The familial form of the illness is associated with mutations in the gene encoding Cu/Zn superoxide dismutase 1 (SOD-1) enzyme, but it accounts for fewer than 10% of cases; the rest, more than 90%, correspond to the sporadic form of ALS. Although many proposals have been suggested over the years, the mechanisms underlying the characteristic selective killing of MN in ALS remain unknown. In this study we tested the effect of sera from sporadic ALS patients on NMDA receptors (NMDAR). We hypothesize that an endogenous seric factor is implicated in neuronal death in ALS, mediated by the modulation of NMDAR. Sera from ALS patients and from healthy subjects were pretreated to inactivate complement pathways and dialyzed to remove glutamate and glycine. IgGs from ALS patients and healthy subjects were obtained by affinity chromatography and dialyzed against phosphate-buffered saline. Human NMDAR were expressed in Xenopus laevis oocytes, and ionic currents were recorded using the two-electrode voltage clamp technique. Sera from sporadic ALS patients induced transient oscillatory currents in oocytes expressing NMDAR with a significantly higher total electrical charge than that induced by sera from healthy subjects. Sera from patients with other neuromuscular diseases did not exert this effect. The currents were inhibited by MK-801, a noncompetitive blocker of NMDAR. The PLC inhibitor, U-73122, and the IP(3) receptor antagonist, 2-APB, also inhibited the sera-induced currents. The oscillatory signal recorded was due to internal calcium mobilization. Isolated IgGs from ALS patients significantly affected the activity of oocytes injected with NMDAR, causing a 2-fold increase over the response recorded for IgGs from healthy subjects. Our data support the notion that ALS sera contain soluble factors that mobilize intracellular calcium, not opening directly the ionic conductance, but through the non-canonical activation of NMDAR.

Antibodies against disialosyl and terminal NeuNAc(α2-3)Gal ganglioside epitopes in acute relapsing sensory ataxic neuropathy

JO N 2 80 3 Neurological examination revealed ophthalmoplegia and gait ataxia with a positive Romberg’s sign. Deep tendon reflexes were absent as was sensation to vibration up to the knees and elbows. Sensory loss mainly affecting propioceptive and kinesthetic sensations was predominant in lower limbs. Bulbar involvement was manifested by the presence of dysphagia, nasal voice and phonation difficulties. Muscle strength was normal. Electrophysiologic findings were consistent with a demyelinating sensorymotor polyneuropathy. CSF was acellular with elevated protein levels (1.200 g/L, normal < 0.450 g/ L). Serum immunofixation revealed an IgM-κ type M component. Cold agglutinins were present. Screening tests for malignancy, serum level of vitamin B12 and E, folate, VDRL and HIV, anti-Ro and anti-La antibodies, and anti-MAG antibodies were normal or negative. The patient improved after a course of intravenous immunoglobulins (0.4 g/kg body weight) and symptoms resolved completely. Nine years later he developed a similar episode, following another upper respiratory tract infection, and spontaneously recovered two weeks later. Serum samples were obtained during the acute phase of both episodes and six months later. ELISA showed high titres of serum antiGM3 (1:25500), GD1a (1:1100), Ricard Rojas-Garcia Eduard Gallardo Monica Povedano Noemi de Luna Jordi Bruna Candido Juarez Jordi Diaz-Manera Juan Antonio Martinez-Matos Isabel Illa

Amyotrophic lateral sclerosis: A higher than expected incidence in people over 80 years of age

Abstract Our objective was to determine the age-specific incidence and clinical-epidemiological characteristics of an amyotrophic lateral sclerosis (ALS) cohort of patients in Catalonia (Spain). New cases diagnosed between 1 January 2004 and 31 December 2013 were 41 (20 males and 21 females), with an annual crude incidence rate of 2.7 per 100,000 person-years (95% CI 1.90–3.59). The incidence rate increased with age reaching a peak in the age group of 70–79 years. There was a non-significant decrease in the incidence rate in the group of patients over 80 years (p-value = 0.75) at 17.99 per 100,000 person years (95% CI 7.81–28.17). The percentage of patients over 80 years of age was 29.3% and over age 85 years was 9.8%. The prevalence rate at the end of the study period was 8.38/100,000 of the total population. Mean age at symptom onset was 76.0 years. Onset of symptoms was bulbar or generalized in 36.6% of cases. In conclusion, ALS incidence in Osona is within the range of other countries across Europe. Our results suggest that the age-specific incidence rate of ALS increases with age through the oldest age groups suggesting an age-risk effect to develop the disease.

Complex Inflammation mRNA-Related Response in ALS Is Region Dependent

Inflammatory changes are analyzed in the anterior spinal cord and frontal cortex area 8 in typical spinal-predominant ALS cases. Increased numbers of astrocytes and activated microglia are found in the anterior horn of the spinal cord and pyramidal tracts. Significant increased expression of TLR7, CTSS, and CTSC mRNA and a trend to increased expression of IL10RA, TGFB1, and TGFB2 are found in the anterior lumbar spinal cord in ALS cases compared to control cases, whereas C1QTNF7 and TNFRSF1A mRNA expression levels are significantly decreased. IL6 is significantly upregulated and IL1B shows a nonsignificant increased expression in frontal cortex area 8 in ALS cases. IL-6 immunoreactivity is found in scattered monocyte-derived macrophages/microglia and TNF-α in a few cells of unknown origin in ALS cases. Increased expression and abnormal distribution of IL-1β occurred in motor neurons of the lumbar spinal cord in ALS. Strong IL-10 immunoreactivity colocalizes with TDP-43-positive inclusions in motor neurons in ALS cases. The present observations show a complex participation of cytokines and mediators of the inflammatory response in ALS consistent with increased proinflammatory cytokines and sequestration of anti-inflammatory IL-10 in affected neurons.

A novel small deletion in PMP22 causes a mild hereditary neuropathy with liability to pressure palsies phenotype

Introduction: In this study we examined a family with electrophysiological findings of hereditary neuropathy with liability to pressure palsies (HNPP) and a mild clinical presentation.Methods: Four members of a family were referred for diagnosis of HNPP. Electrophysiological studies included motor and sensory nerve conduction studies in the upper and lower extremities. Investigations of microsatellites, using polymorphic repeat markers flanking the gene, and multiplex ligation‐dependent probe amplification (MLPA) were performed for molecular studies. Results: The initial study of microsatellites did not detect any change, but MLPA demonstrated a small deletion of exon 5 in the PMP22 gene. Conclusion: Our findings demonstrate the important role of small deletions in the PMP22 gene in the etiology of HNPP with a normal microsatellite study. Muscle Nerve 45: 135–138, 2012

Early and gender-specific differences in spinal cord mitochondrial function and oxidative stress markers in a mouse model of ALS

IntroductionAmyotrophic lateral sclerosis (ALS) is a motor neuron disease with a gender bias towards major prevalence in male individuals. Several data suggest the involvement of oxidative stress and mitochondrial dysfunction in its pathogenesis, though differences between genders have not been evaluated. For this reason, we analysed features of mitochondrial oxidative metabolism, as well as mitochondrial chain complex enzyme activities and protein expression, lipid profile, and protein oxidative stress markers, in the Cu,Zn superoxide dismutase with the G93A mutation (hSOD1-G93A)- transgenic mice and Neuro2A(N2A) cells overexpressing hSOD1-G93A.Results and ConclusionsOur results show that overexpression of hSOD1-G93A in transgenic mice decreased efficiency of mitochondrial oxidative phosphorylation, located at complex I, revealing a temporal delay in females with respect to males associated with a parallel increase in selected markers of protein oxidative damage. Further, females exhibit a fatty acid profile with higher levels of docosahexaenoic acid at 30 days. Mechanistic studies showed that hSOD1-G93A overexpression in N2A cells reduced complex I function, a defect prevented by 17β-estradiol pretreatment. In conclusion, ALS-associated SOD1 mutation leads to delayed mitochondrial dysfunction in female mice in comparison with males, in part attributable to the higher oestrogen levels of the former. This study is important in the effort to further understanding of whether different degrees of spinal cord mitochondrial dysfunction could be disease modifiers in ALS.