A Maori specific RFC1 pathogenic repeat configuration in CANVAS, likely due to a founder allele.

Cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS) is a recently recognized neurodegenerative disease with onset in mid- to late adulthood. The genetic basis for a large proportion of Caucasian patients was recently shown to be the biallelic expansion of a pentanucleotide (AAGGG)n repeat in RFC1. Here, we describe the first instance of CANVAS genetic testing in New Zealand Maori and Cook Island Maori individuals. We show a novel, possibly population-specific CANVAS configuration (AAAGG)10-25(AAGGG)exp, which was the cause of CANVAS in all patients. There were no apparent phenotypic differences compared with European CANVAS patients. Presence of a common disease haplotype among this cohort suggests this novel repeat expansion configuration is a founder effect in this population, which may indicate that CANVAS will be especially prevalent in this group. Haplotype dating estimated the most recent common ancestor at ∼1430 ce. We also show the same core haplotype as previously described, supporting a single origin of the CANVAS mutation.

Long Exercise Test in Periodic Paralysis: A Bayesian Analysis.

INTRODUCTION: The long exercise test (LET) is used to assess the diagnosis of periodic paralysis (PP), but LET methodology and normal "cutoff" values vary. METHODS: To determine optimal LET methodology and cutoffs, we reviewed LET data (abductor digiti minimi motor response amplitude, area) from 55 patients with PP (32 genetically definite) and 125 controls. Receiver operating characteristic curves were constructed, and area under the curve (AUC) was calculated to compare (1) peak-to-nadir versus baseline-to-nadir methodologies and (2) amplitude versus area decrements. Using bayesian principles, we calculated optimal cutoff decrements that achieved 95% posttest probability of PP for various pretest probabilities (PreTPs). RESULTS: AUC was highest for peak-to-nadir methodology and equal for amplitude and area decrements. For PreTP ≤ 50%, optimal decrement cutoffs (peak-to-nadir) were > 40% (amplitude) or > 50% (area). DISCUSSION: For confirmation of PP, our data endorse the diagnostic utility of peak-to-nadir LET methodology using 40% amplitude or 50% area decrement cutoffs for PreTP ≤50%. Muscle Nerve 59:47-54, 2019.

Autonomic dysfunction is a major feature of cerebellar ataxia, neuropathy, vestibular areflexia 'CANVAS' syndrome.

Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is a recently recognized neurodegenerative ganglionopathy. Prompted by the presence of symptomatic postural hypotension in two patients with CANVAS, we hypothesized that autonomic dysfunction may be an associated feature of the syndrome. We assessed symptoms of autonomic dysfunction and performed autonomic nervous system testing among 26 patients from New Zealand. After excluding three patients with diabetes mellitus, 83% had evidence of autonomic dysfunction; all patients had at least one autonomic symptom and 91% had more than two symptoms. We also found a higher rate of downbeat nystagmus (65%) than previously described in CANVAS. We confirmed that sensory findings on nerve conduction tests were consistent with a sensory ganglionopathy and describe two patients with loss of trigeminal sensation consistent with previous pathological descriptions of trigeminal sensory ganglionopathy. Our results suggest that autonomic dysfunction is a major feature of CANVAS. This has implications for the management of patients with CANVAS as the autonomic symptoms may be amenable to treatment. The findings also provide an important differential diagnosis from multiple system atrophy for patients who present with ataxia and autonomic failure.

Non-dystrophic myotonia: prospective study of objective and patient reported outcomes.

Non-dystrophic myotonias are rare diseases caused by mutations in skeletal muscle chloride and sodium ion channels with considerable phenotypic overlap between diseases. Few prospective studies have evaluated the sensitivity of symptoms and signs of myotonia in a large cohort of patients. We performed a prospective observational study of 95 participants with definite or clinically suspected non-dystrophic myotonia recruited from six sites in the USA, UK and Canada between March 2006 and March 2009. We used the common infrastructure and data elements provided by the NIH-funded Rare Disease Clinical Research Network. Outcomes included a standardized symptom interview and physical exam; the Short Form-36 and the Individualized Neuromuscular Quality of Life instruments; electrophysiological short and prolonged exercise tests; manual muscle testing; and a modified get-up-and-go test. Thirty-two participants had chloride channel mutations, 34 had sodium channel mutations, nine had myotonic dystrophy type 2, one had myotonic dystrophy type 1, and 17 had no identified mutation. Phenotype comparisons were restricted to those with sodium channel mutations, chloride channel mutations, and myotonic dystrophy type 2. Muscle stiffness was the most prominent symptom overall, seen in 66.7% to 100% of participants. In comparison with chloride channel mutations, participants with sodium mutations had an earlier age of onset of stiffness (5 years versus 10 years), frequent eye closure myotonia (73.5% versus 25%), more impairment on the Individualized Neuromuscular Quality of Life summary score (20.0 versus 9.44), and paradoxical eye closure myotonia (50% versus 0%). Handgrip myotonia was seen in three-quarters of participants, with warm up of myotonia in 75% chloride channel mutations, but also 35.3% of sodium channel mutations. The short exercise test showed ≥10% decrement in the compound muscle action potential amplitude in 59.3% of chloride channel participants compared with 27.6% of sodium channel participants, which increased post-cooling to 57.6% in sodium channel mutations. In evaluation of patients with clinical and electrical myotonia, despite considerable phenotypic overlap, the presence of eye closure myotonia, paradoxical myotonia, and an increase in short exercise test sensitivity post-cooling suggest sodium channel mutations. Outcomes designed to measure stiffness or the electrophysiological correlates of stiffness may prove useful for future clinical trials, regardless of underlying mutation, and include patient-reported stiffness, bedside manoeuvres to evaluate myotonia, muscle specific quality of life instruments and short exercise testing.

Radioactive iodine treatment for Graves' hyperthyroidism: incidence of Graves orbitopathy.

PURPOSE: There are limited recent data on the effect of radioactive iodine (RAI) for Graves' disease on Graves' orbitopathy (GO) development or reactivation. This audit investigates the GO incidence in patients with Graves' disease after RAI treatment, and explores risk factors present, and steroid prophylaxis use. METHODS: A retrospective audit of Graves' disease patients treated with RAI over a 5-year period. Data collected: smoking status, thyroid-stimulating hormone receptor antibody (TRAb) status, GO history, Graves' disease duration, eye features pre- and post-treatment, prophylactic corticosteroids, RAI dose given, post-RAI thyroid status, duration until hypothyroid. RESULTS: One hundred one patients were included, with a median Graves' disease duration 36 months. 34/101 (33.7%) were active/ex-smokers, 86/101 (85.1%) were TRAb-positive, 11/101 (10.9%) had a GO history; 32 (31.7%) had eye features present. Median RAI dose given was 596MBq. 8/101 (7.9%) patients received prophylactic corticosteroid; 89/101 (88.1%) achieved hypothyroid state in the year after RAI. GO developed in 5/101 (5.0%), of which 4/5 (80%) were de novo in high-risk individuals who did not receive steroids. One was a GO reactivation despite steroids. Two required intravenous steroids with/without orbital radiotherapy, one completed oral steroid taper; the remainder were treated conservatively. CONCLUSION: Our cohort had a lower GO incidence in patients with Graves' disease receiving RAI, with majority arising de novo . It is essential that all patients are assessed for Graves orbitopathy risk factors and counselled adequately prior to RAI. The decision to initiate steroids should be undertaken in a multi-disciplinary setting involving endocrinologists and ophthalmologists.

Neuronal intranuclear inclusion disease in New Zealand: A novel discovery.

Neuronal intranuclear inclusion disease, caused by a GGC repeat expansion in the 5'-untranslated region of NOTCH2NLC, is a rare neurodegenerative condition with highly variable clinical manifestations. In recent years, the number of reported cases have increased dramatically in East Asia. We report the first four genetically confirmed cases of neuronal intranuclear inclusion disease in New Zealand, all having Polynesian ancestry (three New Zealand Maori and one Cook Island Maori). Phenotypically, they resemble cases reported from recent large East Asian cohorts.

SpliceSeq: a resource for analysis and visualization of RNA-Seq data on alternative splicing and its functional impacts.

SUMMARY: SpliceSeq is a resource for RNA-Seq data that provides a clear view of alternative splicing and identifies potential functional changes that result from splice variation. It displays intuitive visualizations and prioritized lists of results that highlight splicing events and their biological consequences. SpliceSeq unambiguously aligns reads to gene splice graphs, facilitating accurate analysis of large, complex transcript variants that cannot be adequately represented in other formats. AVAILABILITY AND IMPLEMENTATION: SpliceSeq is freely available at http://bioinformatics.mdanderson.org/main/SpliceSeq:Overview. The application is a Java program that can be launched via a browser or installed locally. Local installation requires MySQL and Bowtie. CONTACT: mryan@insilico.us.com SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Evolutionary dynamics of whole-body regeneration across planarian flatworms.

Regenerative abilities vary dramatically across animals. Even amongst planarian flatworms, well-known for complete regeneration from tiny body fragments, some species have restricted regeneration abilities while others are almost entirely regeneration incompetent. Here, we assemble a diverse live collection of 40 planarian species to probe the evolution of head regeneration in the group. Combining quantification of species-specific head-regeneration abilities with a comprehensive transcriptome-based phylogeny reconstruction, we show multiple independent transitions between robust whole-body regeneration and restricted regeneration in freshwater species. RNA-mediated genetic interference inhibition of canonical Wnt signalling in RNA-mediated genetic interference-sensitive species bypassed all head-regeneration defects, suggesting that the Wnt pathway is linked to the emergence of planarian regeneration defects. Our finding that Wnt signalling has multiple roles in the reproductive system of the model species Schmidtea mediterranea raises the possibility that a trade-off between egg-laying, asexual reproduction by fission/regeneration and Wnt signalling drives regenerative trait evolution. Although quantitative comparisons of Wnt signalling levels, yolk content and reproductive strategy across our species collection remained inconclusive, they revealed divergent Wnt signalling roles in the reproductive system of planarians. Altogether, our study establishes planarians as a model taxon for comparative regeneration research and presents a framework for the mechanistic evolution of regenerative abilities.

SpliceCenter: a suite of web-based bioinformatic applications for evaluating the impact of alternative splicing on RT-PCR, RNAi, microarray, and peptide-based studies.

BACKGROUND: Over 60% of protein-coding genes in vertebrates express mRNAs that undergo alternative splicing. The resulting collection of transcript isoforms poses significant challenges for contemporary biological assays. For example, RT-PCR validation of gene expression microarray results may be unsuccessful if the two technologies target different splice variants. Effective use of sequence-based technologies requires knowledge of the specific splice variant(s) that are targeted. In addition, the critical roles of alternative splice forms in biological function and in disease suggest that assay results may be more informative if analyzed in the context of the targeted splice variant. RESULTS: A number of contemporary technologies are used for analyzing transcripts or proteins. To enable investigation of the impact of splice variation on the interpretation of data derived from those technologies, we have developed SpliceCenter. SpliceCenter is a suite of user-friendly, web-based applications that includes programs for analysis of RT-PCR primer/probe sets, effectors of RNAi, microarrays, and protein-targeting technologies. Both interactive and high-throughput implementations of the tools are provided. The interactive versions of SpliceCenter tools provide visualizations of a gene's alternative transcripts and probe target positions, enabling the user to identify which splice variants are or are not targeted. The high-throughput batch versions accept user query files and provide results in tabular form. When, for example, we used SpliceCenter's batch siRNA-Check to process the Cancer Genome Anatomy Project's large-scale shRNA library, we found that only 59% of the 50,766 shRNAs in the library target all known splice variants of the target gene, 32% target some but not all, and 9% do not target any currently annotated transcript. CONCLUSION: SpliceCenter http://discover.nci.nih.gov/splicecenter provides unique, user-friendly applications for assessing the impact of transcript variation on the design and interpretation of RT-PCR, RNAi, gene expression microarrays, antibody-based detection, and mass spectrometry proteomics. The tools are intended for use by bench biologists as well as bioinformaticists.

Antagonistic Self-Organizing Patterning Systems Control Maintenance and Regeneration of the Anteroposterior Axis in Planarians.

Planarian flatworms maintain their body plan in the face of constant internal turnover and can regenerate from arbitrary tissue fragments. Both phenomena require self-maintaining and self-organizing patterning mechanisms, the molecular mechanisms of which remain poorly understood. We show that a morphogenic gradient of canonical Wnt signaling patterns gene expression along the planarian anteroposterior (A/P) axis. Our results demonstrate that gradient formation likely occurs autonomously in the tail and that an autoregulatory module of Wnt-mediated Wnt expression both shapes the gradient at steady state and governs its re-establishment during regeneration. Functional antagonism between the tail Wnt gradient and an unknown head patterning system further determines the spatial proportions of the planarian A/P axis and mediates mutually exclusive molecular fate choices during regeneration. Overall, our results suggest that the planarian A/P axis is patterned by self-organizing patterning systems deployed from either end that are functionally coupled by mutual antagonism.

Hypoventilation in glycine-receptor antibody related progressive encephalomyelitis, rigidity and myoclonus.

Glycine receptor (GlyR) antibodies have been identified in patients with rigidity and hyperekplexia, but the clinical phenotype associated with these antibodies has not been fully elucidated. The clinical features in two additional patients with GlyR antibodies are described. A 55-year-old man presented with stimulus-induced hyperekplexia and rigidity in the lower limbs and trunk. He initially responded to benzodiazepines, but presented after 18 months with severe, painful, prolonged spasms associated with supraventricular and ventricular arrhythmias, hypoventilation and oxygen desaturation requiring intubation. He improved following treatment with clonazepam, baclofen and immunomodulatory therapies. A 58-year-old woman presented with stiffness in the legs and hyperekplexia associated with hypoventilation, at times leading to loss of consciousness. She responded to benzodiazepines and has remained in remission. The clinical picture associated with GlyR antibodies includes autonomic dysfunction, cardiac arrhythmias and hypoventilation. It is important to recognise these serious complications early to limit mortality from this treatable condition.

Induction of the Proepicardium.

The proepicardium is a transient extracardiac embryonic tissue that gives rise to the epicardium and a number of coronary vascular cell lineages. This important extracardiac tissue develops through multiple steps of inductive events, from specification of multiple cell lineages to morphogenesis. This article will review our current understanding of inductive events involved in patterning of the proepicardium precursor field, specification of cell types within the proepicardium, and their extension and attachment to the heart.

Treatment of neuromuscular channelopathies: current concepts and future prospects.

Our understanding of the molecular pathogenesis of the neuromuscular ion channelopathies has increased rapidly over the past two decades due to the identification of many of the genes whose mutation causes these diseases. These molecular discoveries have facilitated identification and classification of the hereditary periodic paralyses and the myotonias, and are likely to shed light on acquired ion channelopathies as well. Despite our better understanding of the pathogenesis of these disorders, current treatments are largely empirical and the evidence in favor of specific therapy largely anecdotal. For periodic paralysis, dichlorphenamide--a carbonic anhydrase inhibitor--has been shown in a controlled trial to prevent attacks for many patients with both hypokalemic and hypokalemic periodic paralysis. A second trial, comparing dichlorphenamide with acetazolamide versus placebo, is currently in progress. For myotonia, there is only anecdotal evidence for treatment, but a controlled trial of mexiletine versus placebo is currently being funded by a Food and Drug Administration-orphan products grant and is scheduled to begin in late 2008. In the future, mechanism-based approaches are likely to be developed. For example, exciting advances have already been made in one disorder, myotonic dystrophy-1 (DM-1). In a mouse model of DM-1, a morpholino antisense oligonucleuotide targeting the 3' splice site of CLCN1 exon 7a repaired the RNA splicing defect by promoting the production of full-length chloride channel transcripts. Abnormal chloride conductance was restored, and myotonia was abolished. Similar strategies hold potential for DM-2. The era of molecularly-based treatments is about to begin.

Clinical evaluation of membrane excitability in muscle channel disorders: potential applications in clinical trials.

Muscle channelopathies are inherited disorders that cause paralysis and myotonia. Molecular technology has contributed immeasurably to diagnostic testing, to correlation of genotype with phenotype, and to insight into the pathophysiology of these disorders. In most cases, the diagnosis of muscle channelopathy is still made on clinical grounds, but is supported by ancillary laboratory and electrodiagnostic testing such as serum potassium measurement, exercise testing, repetitive nerve stimulation, needle electromyography, calculation of muscle fiber conduction velocity, or electromyography power spectra. Although provocative glucose or potassium challenges are now infrequently performed, they have contributed greatly to our understanding of the pathophysiology of these disorders, and to our ability to differentiate between periodic paralysis types. Despite considerable progress, ample opportunity remains for future clinical research, particularly in expanding genotype-phenotype correlations and in optimizing electrodiagnostic methods. With respect to diagnostic testing, there is a need for accurate, efficient, and cost-effective bedside testing, given the substantial proportion (as high as 20%) of genetically undefined cases. Even in genetically defined cases, minimal clinical expressivity due to incomplete penetrance poses a significant challenge to currently available nonmolecular testing.