Infusion-related reactions during Natalizumab treatment: Do we still need a post-infusion observation period?

BACKGROUND: Natalizumab (NTZ) is a humanized monoclonal antibody used in the treatment of relapsing remitting multiple sclerosis. Although NTZ is usually well-tolerated, infusion-related reactions (IRRs) may occur, and the patients have to be monitored during the infusion and for one hour afterwards. OBJECTIVE: To identify frequency and severity of IRRs during NTZ infusions and one-hour post-infusion observation period in a clinical practice setting. METHODS: Multicenter, observational study involving three Swiss (Lugano, St. Gallen and Luzern) and two Italian (Milano and Napoli) tertiary MS centers. Predisposing factors to IRRs were investigated using multivariate Cox regression models. RESULTS: A total of 11'133 infusions received by 302 MS patients were analyzed (68.9% females, median age 33.6 years, median EDSS 2.5). IRRs occurred in 24 (8%) patients during NTZ infusions and in 7 (2%) during one-hour post-infusion. Only 8 patients needed pharmacological treatment, of whom 7 during NTZ infusion. Age, sex and history of allergies were not associated with risks for IRR. The frequency of post infusion IRRs after the fifth cycle was low compared to that during the first four infusions (0.83% vs 0.06%). CONCLUSION: In our cohort, NTZ associated IRR mainly occurred during the infusion period compared to the one-hour observational period. Also, the first IRR exclusively occurred within the first 4 NTZ administrations. However, further multi-center studies with a larger sample size are needed to capture rare and serious events that could emerge during the observational period and to make clinical recommendations.

A novel heterozygous variant in ERLIN2 causes autosomal dominant pure hereditary spastic paraplegia.

BACKGROUND AND PURPOSE: Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous monogenic disorders. To date, nearly 70 genes are known to be causative. The aim of this project was to identify the genetic cause of autosomal dominantly inherited pure HSP in two large, unrelated non-consanguineous families. METHODS: The two families were characterized clinically and selected members underwent whole exome sequencing. Potentially disease-causing variants were confirmed by Sanger sequencing and their functional consequences on protein function were predicted by bioinformatic prediction tools. RESULTS: The patients presented with pure spastic paraplegia with age of onset between 9 and 46 years. In both families, a novel heterozygous missense variant in ERLIN2, c.386G>C; p.Ser129Thr, was the only potentially pathogenic variant identified that segregated with the disease. CONCLUSIONS: Biallelic variants in ERLIN2 are known to cause recessive HSP type SPG18. Here, the first two families with an autosomal dominant, pure form of HSP caused by a novel ERLIN2 heterozygous missense variant are described. These findings expand the mutational and inheritance spectrum of SPG18. ERLIN2 variants should also be considered in the diagnostic evaluation of patients with autosomal dominant HSP.

Real-life long-term effectiveness of fingolimod in Swiss patients with relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: In 2011, fingolimod was approved in Switzerland for the treatment of relapsing-remitting multiple sclerosis (RRMS). The aim of the present study was to assess the effectiveness and retention of fingolimod in a real-life Swiss setting, in which patients can receive fingolimod as both first- and second-line treatment for RRMS. METHODS: This cross-sectional, observational study with retrospective data collection was performed at 19 sites that comprised both hospitals and office-based physicians across Switzerland. Sites were asked to document eligible patients in consecutive chronological order to avoid selection bias. Demographic and clinical data from 274 consenting adult patients with RRMS who had received treatment with fingolimod were analyzed. RESULTS: Mean treatment duration with fingolimod was 32 months. Under fingolimod, 77.7% of patients remained free from relapses and 90.3% did not experience disability progression. The proportion of patients who were free from any clinical disease activity, i.e. without relapses and disability progression, was 72.1%. A total of 28.5% of patients had been RRMS treatment-naïve prior to fingolimod therapy. High long-term treatment retention rates ranging between 95.7% at 24 months and 87.8% at 36 months were observed. CONCLUSION: In this Swiss cohort of naïve and pre-treated subjects with RRMS, the majority of patients under fingolimod treatment showed freedom from relapses and disability progression. In addition, treatment retention rate over 2 and 3 years was high, irrespective of previous treatment.

Corticospinal output during muscular fatigue differs in multiple sclerosis patients compared to healthy controls.

BACKGROUND: In multiple sclerosis (MS), fatigue is a common and often disabling symptom. It has multiple causes with central motor fatigue playing an important role. OBJECTIVE: The objective of this study was to analyse the central motor conduction changes in relation to muscle contraction force during muscle fatigue and recovery in MS patients compared to healthy controls. METHODS: A total of 23 MS patients with fatigue and 13 healthy subjects were assessed during 2 minutes of fatiguing exercise of the abductor digiti minimi muscle of the hand and the subsequent 7 minutes of recovery. Central motor conduction was quantified by transcranial magnetic stimulation using the triple stimulation protocol and calculating a central conduction index (CCI). RESULTS: Force declined to 36% of the pre-exercise level (SD 16%; p < 0.01) in MS patients and to 44% (SD 9%, p < 0.01) in healthy subjects (group differences, not statistically significant). The decline of the CCI was significantly less marked in patients (-20%, SD 26%, p < 0.05) than in healthy subjects (-57%, SD 15%, p < 0.05; group differences, p < 0.05). The decline of force and CCI were not correlated in either group. CONCLUSIONS: During a fatiguing exercise, the decline in central motor conduction is significantly less pronounced in MS patients than healthy subjects, although the reduction of force is similar.

Paroxysmal choreoathetosis/spasticity (DYT9) is caused by a GLUT1 defect.

OBJECTIVE: Mutations in SLC2A1, encoding the glucose transporter type 1 (GLUT1), cause a broad spectrum of neurologic disorders including classic GLUT1 deficiency syndrome, paroxysmal exercise-induced dyskinesia (PED, DYT18), and absence epilepsy. A large German/Dutch pedigree has formerly been described as paroxysmal choreoathetosis/spasticity (DYT9) and linked close to but not including the SLC2A1 locus on chromosome 1p. We tested whether 1) progressive spastic paraparesis, in addition to PED, as described in DYT9, and 2) autosomal dominant forms of hereditary spastic paraparesis (HSP) without PED are caused by SLC2A1 defects. METHODS: The German/Dutch family and an Australian monozygotic twin pair were clinically (re-)investigated, and 139 index cases with dominant or sporadic HSP in which relevant dominant genes were partially excluded were identified from databanks. SLC2A1 was sequenced in all cases in this observational study and the functional effects of identified sequence variations were tested in glucose uptake and protein expression assays. RESULTS: We identified causative mutations in SLC2A1 in both families, which were absent in 400 control chromosomes, cosegregated with the affection status, and decreased glucose uptake in functional assays. In the 139 index patients with HSP without paroxysmal dyskinesias, we only identified one sequence variation, which, however, neither decreased glucose uptake nor altered protein expression. CONCLUSIONS: This study shows that DYT9 and DYT18 are allelic disorders and enlarges the spectrum of GLUT1 phenotypes, now also including slowly progressive spastic paraparesis combined with PED. SLC2A1 mutations were excluded as a cause of HSP without PED in our cohort.

Expression profiling in peripheral blood reveals signature for penetrance in DYT1 dystonia.

DYT1 dystonia is an autosomal-dominantly inherited movement disorder, which is usually caused by a GAG deletion in the TOR1A gene. Due to the reduced penetrance of approximately 30-40%, the determination of the mutation in a subject is of limited use with regard to actual manifestation of symptoms. In the present study, we used Affymetrix oligonucleotide microarrays to analyze global gene expression in blood samples of 15 manifesting and 15 non-manifesting mutation carriers in order to identify a susceptibility profile beyond the GAG deletion which is associated with the manifestation of symptoms in DYT1 dystonia. We identified a genetic signature which distinguished between asymptomatic mutation carriers and symptomatic DYT1 patients with 86.7% sensitivity and 100% specificity. This genetic signature could correctly predict the disease state in an independent test set with a sensitivity of 87.5% and a specificity of 85.7%. Conclusively, this genetic signature might provide a possibility to distinguish DYT1 patients from asymptomatic mutation carriers.

[Genetics of dystonia]. / Genetik der Dystonien.

The dystonias comprise a heterogeneous group of movement disorders. In contrast to the frequent sporadic forms, a variety of rare familial forms are caused by genetic mutations with mendelian inheritance. In recent years, significant progress has been made with regard to the identification of genes causing dystonia, and to the molecular pathophysiology underlying dystonic symptoms. Currently, 18 gene loci have been described causing primary dystonia, dystonia-plus syndromes or paroxysmal dystonia. The most frequent form of inherited dystonia, according to current knowledge, is early-onset generalized DYT1 dystonia, caused by a deletion of three basepairs, GAG, in the DYT1 (TOR1A) gene. It is thought that the protein encoded by this gene, torsinA, participates in association of the endoplasmatic reticulum and the nuclear envelope with the cytoskeleton and hereby might influence the reaction of cells to various stresses and/or the development of specific neuronal populations involved in movement control in the brain. Other genes which have only recently been identified include: THAP1, causing adolescent-onset primary dystonia of mixed type (DYT6); ATP1A3, responsible for Rapid-Onset Dystonia-Parkinsonism (RDP, DYT12); PRKRA, causing young-onset dystonia-parkinsonism (DYT16); and SLC2A1, causing paroxysmal exertion-induced dystonia with haemolytic anemia (DYT18). Further, five other loci for primary dystonia (DYT2, DYT4, DYT7, DYT13 and DYT17) have been identified, for which the causative genes remain to be discovered.

Strong genetic evidence for association of TOR1A/TOR1B with idiopathic dystonia.

Recently, association of a TOR1A(DYT1)/TOR1B risk haplotype with common forms of idiopathic dystonia has been reported in the Icelandic population. Here we report a strong association of two single nucleotide polymorphisms within or in close proximity to the TOR1A 3'UTR, with the lowest p value being 0.000008, in a larger cohort of German and Austrian patients with predominantly focal sporadic dystonia.

Possible gender-dependent association of vascular endothelial growth factor (VEGF) gene and ALS.

Individuals homozygous for haplotypes -2578-A/-1154-A/-634-G or -2578-A/-1154-G/-634-G in the promoter/5'UTR of the VEGF gene have a 1.8-fold increased risk of ALS in several European populations. We did not observe any significant association with single markers, or haplotype pairs, in a German sample of 580 sporadic ALS patients and 628 controls. However, the promoter SNP-1154 (rs1570360) was associated with affection status in women (p = 0.036), suggesting that the VEGF effect may be dependent on the sex ratio of the sample.

The alpha-synuclein gene in multiple system atrophy.

BACKGROUND: The formation of alpha-synuclein aggregates may be a critical event in the pathogenesis of multiple system atrophy (MSA). However, the role of this gene in the aetiology of MSA is unknown and untested. METHOD: The linkage disequilibrium (LD) structure of the alpha-synuclein gene was established and LD patterns were used to identify a set of tagging single nucleotide polymorphisms (SNPs) that represent 95% of the haplotype diversity across the entire gene. The effect of polymorphisms on the pathological expression of MSA in pathologically confirmed cases was also evaluated. RESULTS AND CONCLUSION: In 253 Gilman probable or definite MSA patients, 457 possible, probable, and definite MSA cases and 1472 controls, a frequency difference for the individual tagging SNPs or tag-defined haplotypes was not detected. No effect was observed of polymorphisms on the pathological expression of MSA in pathologically confirmed cases.

The fragile X tremor ataxia syndrome in the differential diagnosis of multiple system atrophy: data from the EMSA Study Group.

The recent identification of fragile X-associated tremor ataxia syndrome (FXTAS) associated with premutations in the FMR1 gene and the possibility of clinical overlap with multiple system atrophy (MSA) has raised important questions, such as whether genetic testing for FXTAS should be performed routinely in MSA and whether positive cases might affect the specificity of current MSA diagnostic criteria. We genotyped 507 patients with clinically diagnosed or pathologically proven MSA for FMR1 repeat length. Among the 426 clinically diagnosed cases, we identified four patients carrying FMR1 premutations (0.94%). Within the subgroup of patients with probable MSA-C, three of 76 patients (3.95%) carried premutations. We identified no premutation carriers among 81 patients with pathologically proven MSA and only one carrier among 622 controls (0.16%). Our results suggest that, with proper application of current diagnostic criteria, FXTAS is very unlikely to be confused with MSA. However, slowly progressive disease or predominant tremor are useful red flags and should prompt the consideration of FXTAS. On the basis of our data, the EMSA Study Group does not recommend routine FMR1 genotyping in typical MSA patients.

Service-based survey of dystonia in munich.

We performed a service-based epidemiological study of dystonia in Munich, Germany. Due to favourable referral and treatment patterns in the Munich area, we could provide confident data from dystonia patients seeking botulinum toxin treatment. A total of 230 patients were ascertained, of whom 188 had primary dystonia. Point prevalence ratios were estimated to be 10.1 (95% confidence interval 8.4-11.9) per 100,000 for focal and 0.3 (0.0-0.6) for generalised primary dystonia. The most common focal primary dystonias were cervical dystonia with 5.4 (4.2-6.7) and essential blepharospasm with 3.1 (2.1-4.1) per 100,000 followed by laryngeal dystonia (spasmodic dysphonia) with 1.0 (0.4-1.5) per 100,000.

TorsinA: movement at many levels.

TorsinA is the causative protein in the human neurologic disease early onset torsin dystonia, a movement disorder involving dysfunction in the basal ganglia without apparent neurodegeneration. Most cases result from a dominantly acting three-base pair deletion in the TOR1A gene causing loss of a glutamic acid near the carboxyl terminus of torsinA. Torsins are members of the AAA(+) superfamily of ATPases and are present in all multicellular organisms. Initial studies suggest that torsinA is an ER protein involved in chaperone functions and/or membrane movement.

Novel mutation in the TOR1A (DYT1) gene in atypical early onset dystonia and polymorphisms in dystonia and early onset parkinsonism.

Dystonia is a movement disorder involving sustained muscle contractions and abnormal posturing with a strong hereditary predisposition and without a distinct neuropathology. In this study the TOR1A (DYT1) gene was screened for mutations in cases of early onset dystonia and early onset parkinsonism (EOP), which frequently presents with dystonic symptoms. In a screen of 40 patients, we identified three variations, none of which occurred in EOP patients. Two infrequent intronic single base pair (bp) changes of unknown consequences were found in a dystonia patient and the mother of an EOP patient. An 18-bp deletion (Phe323_Tyr328del) in the TOR1A gene was found in a patient with early onset dystonia and myoclonic features. This deletion would remove 6 amino acids close to the carboxy terminus, including a putative phosphorylation site of torsinA. This 18-bp deletion is the first additional mutation, beyond the GAG-deletion (Glu302/303del), to be found in the TOR1A gene, and is associated with a distinct type of early onset dystonia.

The DYT1 GAG deletion is infrequent in sporadic and familial writer' s cramp.

A 3-base pair (GAG) deletion in the DYT1 gene has recently been found to be responsible for most cases of early-onset primary generalized dystonia. In some cases, this mutation has been associated with writer's cramp. To determine the frequency of this mutation in a larger series of patients, we examined 44 index patients with sporadic or familial (seven patients) writer's cramp for the presence of the DYT1 GAG deletion, including eight patients with segmental dystonia involving at least one upper limb. We found the mutation in none of these index patients, which confirms that isolated writer's cramp is only in rare cases a phenotypic manifestation of this mutation, even if a positive family history of writer's cramp is present.

GAG deletion in the DYT1 gene in early limb-onset idiopathic torsion dystonia in Germany.

We examined 57 patients with idiopathic torsion dystonia (ITD) for the 3-bp GAG deletion in the DYT1 gene on human chromosome 9q34. Three of five patients with early limb-onset ITD, one of them with a positive family history, tested positive for the mutation, as did one young patient with multifocal dystonia and a short course of the disease. Two patients with early-onset generalized dystonia beginning in the cervical muscles, as well as five other patients with multifocal, 14 patients with segmental, and 30 patients with focal cervical dystonia did not carry the mutation. This suggests that the GAG deletion is responsible for a major portion of cases of typical early limb-onset dystonia, but not for other types of dystonia, in our population.

Highly purified oligo-His tagged human recombinant alpha(1)-AChR is immunogenic in vivo and suitable for T cell stimulation in vitro in experimental and human myasthenia gravis.

Using recombinantly expressed proteins for selection of antigen-specific T cell lines carries a high risk of selecting T cells specific for contaminating proteins. This risk is especially high for very hydrophobic proteins which are notoriously difficult to purify, such as the integral membrane protein acetylcholine receptor (AChR). We prepared a highly purified recombinant AChR by adding an oligo-histidine affinity-tag to the human alpha(1)-AChR and expressing it in E. coli. This allowed purification by Ni-NTA chromatography and subsequent electroelution from preparative SDS gel as purification steps, resulting in complete purity as assessed by silver stain on SDS-PAGE. This protein preparation induced fatal experimental allergic myasthenia gravis in Lewis rats. Furthermore, the protein could be used to select T cell lines from immunized Lewis rats and patients with myasthenia gravis. However, even with this highly purified protein, one of 8 Lewis rat T cell lines and 3 of 7 human T cell lines cross-reacted to E. coli control proteins. The results show that oligo-histidine tagged, highly purified human alpha(1)-AChR is highly immunogenic in vivo and in vitro.