Functional validation of novel MKS3/TMEM67 mutations in COACH syndrome

COACH syndrome is an autosomal recessive developmental disorder, a subtype of Joubert syndrome and related disorders, characterized by cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, and hepatic fibrosis. Although mutations in TMEM67 (transmembrane protein 67)/MKS3 (Meckel-Gruber syndrome, type 3) were reported to cause COACH syndrome, this causality has not verified by functional studies. In a 20-year-old Korean man, we found cerebellar ataxia, isolated elevation in serum γ-glutamyl transpeptidase (γ-GTP) activity, oligophrenia, the molar tooth sign (MTS) in the brain MR images and congenital hepatic fibrosis (CHF). Two novel compound heterozygous mutations were found in TMEM67 in the patient: i) missense mutation (c.395 G > C and p.Gly132Ala) in exon 3, and ii) deletion in exon 26 (c.2758delT and p.Tyr920ThrfsX40). Western blotting showed that the p.Tyr920ThrfsX40 mutation accelerates turnover of the TMEM67 protein. Although wild-type human TMEM67 RNA rescued phenotypes of zebrafish embryos injected with anti-sense oligonucleotide morpholinos against tmem67, the two human TMEM67 RNAs individually harboring the two mutations did not. Finally, Wnt signaling, but not Hedgehog signaling, was suppressed in tmem67 morphants. To the best of our knowledge, this is the first report verifying the causality between COACH syndrome and TMEM67, which will further our understanding of molecular pathogenesis of the syndrome.

Zebrafish as an animal model in epilepsy studies with multichannel EEG recordings

Despite recent interest in using zebrafish in human disease studies, sparked by their economics, fecundity, easy handling, and homologies to humans, the electrophysiological tools or methods for zebrafish are still inaccessible. Although zebrafish exhibit more significant larval–adult duality than any other animal, most electrophysiological studies using zebrafish are biased by using larvae these days. The results of larval studies not only differ from those conducted with adults but also are unable to delicately manage electroencephalographic montages due to their small size. Hence, we enabled non-invasive long-term multichannel electroencephalographic recording on adult zebrafish using custom-designed electrodes and perfusion system. First, we exploited demonstration of long-term recording on pentylenetetrazole-induced seizure models, and the results were quantified. Second, we studied skin–electrode impedance, which is crucial to the quality of signals. Then, seizure propagations and gender differences in adult zebrafish were exhibited for the first time. Our results provide a new pathway for future neuroscience research using zebrafish by overcoming the challenges for aquatic organisms such as precision, serviceability, and continuous water seepage.

Risk Factors for Aseptic Meningitis in Herpes Zoster Patients

Background

Herpes zoster (HZ) is caused by reactivation of latent varicella-zoster virus (VZV) infection. HZ-associated aseptic meningitis, a rare complication of HZ, can require hospitalization and a long treatment period.

Objective

A retrospective study was performed to identify potential factors associated with HZ-associated aseptic meningitis development.

Methods

We included all outpatients and patients admitted in the neurology and dermatology departments of a single tertiary center, who were diagnosed with HZ for two years. Among 818 patients, 578 patients were eligible for analysis.

Results

The demographics and potential risk factors were compared between the uncomplicated HZ group (n=554) and aseptic meningitis group (n=24). Among the potential factors, the dermatological distribution of skin rash and gender showed statistically significantly different between the two groups. Patients with craniocervical distribution of HZ accounted for 87.5% (n=21) of the aseptic meningitis group and 54.3% (n=301) of the uncomplicated HZ group (p=0.043). The aseptic meningitis group had more men (66.7%, n=16) than the uncomplicated HZ group (42.8%, n=237, p=0.033). Patients with craniocervical distribution had an odds ratio (OR) of 5.884 (p=0.001) for developing aseptic meningitis when compared with the other dermatome involvements. Additional logistic regression analysis resulted in a fading between gender difference (p=0.050) and craniocervical involvement having an OR of 5.667 for aseptic meningitis (p=0.006).

Conclusion

In HZ patients, skin rash with craniocervical distribution and male gender were associated with a higher risk of aseptic meningitis.

The Validity and Reliability of the Korean Version of the Stigma Scale for Chronic Illness 8-Items (SSCI-8) in Patients with Neurological Disorders

PURPOSE

The aim of this study was to develop a Korean version of the Stigma Scale for Chronic Illness 8-items (SSCI-8) and then assess its reliability and construct validity among patients with neurological conditions.

METHOD

Patients diagnosed with stroke, Parkinson's disease, epilepsy, multiple sclerosis, myasthenia gravis, and amyotrophic lateral sclerosis were recruited. Reliability was assessed for internal consistency with Cronbach's alpha coefficient. Exploratory factor analysis (EFA) was used to extract potential factors of Korean SSCI-8. Convergent validity was assessed by correlating scores on the Korean SSCI-8 with scores for depression using the Beck Depression Inventory, anxiety using Spielberger's State-Trait Anxiety Inventory, and functional ability using the Korean modified Barthel Index (K-MBI), respectively.

RESULTS

Of the total 202 patients enrolled in this study, 119 (58.9 %) were recruited with stroke, 33 (16.3 %) with Parkinson's disease, and 29 (14.4 %) with epilepsy. The Korean SSCI-8 had a high internal consistency (Cronbach's alpha = 0.90). The Korean SSCI-8 retrieved one factor from eight items by the EFA, and all factor loading scores were above 0.70 (0.71-0.84). The Korean SSCI-8 was correlated positively with depression (r = 0.74, p < 0.001) and anxiety (r = 0.61, p < 0.001), and negatively with the K-MBI (r = -0.48, p < 0.001).

CONCLUSION

This study shows that the Korean SSCI-8 is a unidimensional model, even though it includes items of both enacted and internalized stigma. It is both reliable and valid for assessing stigma among Korean patients with neurological disease.

Acute bulbar palsy as a variant of Guillain-Barré syndrome

OBJECTIVE

To categorize a syndrome manifesting as prominent acute bulbar palsy (ABP) without limb motor weakness as a variant form of Guillain-Barré syndrome (GBS) and differentiate it from Miller Fisher syndrome (MFS) and pharyngeal-cervical-brachial (PCB) variants.

METHODS

We analyzed cases of ABP without limb motor weakness based on a dataset containing clinical information and the results of antiganglioside antibodies assays for acute immune-mediated neuropathies.

RESULTS

Eleven cases with an age at onset ranging from 18 to 65 years (mean 33.8 years) were identified as ABP-plus syndrome. All of the enrolled cases manifested with ABP as the predominant symptom, and with no limb weakness. The following features accompanied ABP in order of decreasing frequency: ophthalmoplegia (n = 9, 82%), ataxia (n = 9, 82%), and facial palsy (n = 6, 55%). An enzyme-linked immunosorbent assay study disclosed that immunoglobulin G (IgG) anti-GT1a antibodies were the most frequent (n = 11), followed by IgG anti-GQ1b antibodies (n = 6).

CONCLUSIONS

We propose that ABP-plus syndrome without neck or limb weakness is a variant of GBS that is distinct from the MFS and PCB variants. The presence of IgG anti-GT1a antibodies can explain the relationships between the distinct clinical characteristics and the underlying pathomechanisms.

Clinical Implications of Changes in Individual Platelet Reactivity to Aspirin Over Time in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Time-dependent changes in individual platelet reactivity have been detected in patients with coronary artery disease. Therefore, we sought to evaluate the time-dependent changes in platelet reactivity to aspirin during the acute stage after ischemic stroke and the clinical implications of variable patient responses to aspirin in acute ischemic stroke.

METHODS

We conducted a single-center, prospective, observational study. The acute aspirin reaction unit (ARU) was measured after 3 hours of aspirin loading, with higher values indicating increased platelet reactivity despite aspirin therapy. The follow-up ARU was measured on the fifth day of consecutive aspirin intake. The numeric difference between the follow-up ARU and the acute ARU was defined as ΔARU and was stratified into quartiles. Early neurological deterioration was regarded as an early clinical outcome.

RESULTS

Both the acute ARU (476±69 IU) and the follow-up ARU (451±68 IU) were measured in 349 patients in this study. Early neurological deterioration was observed in 72 patients (20.6%). Changes in aspirin platelet reactivity over time showed an approximately Gaussian distribution. The highest ΔARU quartile was independently associated with early neurological deterioration (odds ratio, 3.19; 95% confidence interval, 1.43-7.10; P=0.005) by multivariate logistic regression analysis.

CONCLUSIONS

The results of our study showed that the increase in platelet reactivity to aspirin over time is independently associated with early neurological deterioration in patients with acute ischemic stroke. In addition, during the acute stage of ischemic stroke, serial platelet reactivity assays may be more useful than a single assay for identifying the clinical implications of aspirin platelet reactivity after ischemic stroke.

Zebrafish needle EMG: a new tool for high-throughput drug screens

Zebrafish models have recently been highlighted as a valuable tool in studying the molecular basis of neuromuscular diseases and developing new pharmacological treatments. Needle electromyography (EMG) is needed not only for validating transgenic zebrafish models with muscular dystrophies (MD), but also for assessing the efficacy of therapeutics. However, performing needle EMG on larval zebrafish has not been feasible due to the lack of proper EMG sensors and systems for such small animals. We introduce a new type of EMG needle electrode to measure intramuscular activities of larval zebrafish, together with a method to hold the animal in position during EMG, without anesthetization. The silicon-based needle electrode was found to be sufficiently strong and sharp to penetrate the skin and muscles of zebrafish larvae, and its shape and performance did not change after multiple insertions. With the use of the proposed needle electrode and measurement system, EMG was successfully performed on zebrafish at 30 days postfertilization (dpf) and at 5 dpf. Burst patterns and spike morphology of the recorded EMG signals were analyzed. The measured single spikes were triphasic with an initial positive deflection, which is typical for motor unit action potentials, with durations of ∼10 ms, whereas the muscle activity was silent during the anesthetized condition. These findings confirmed the capability of this system of detecting EMG signals from very small animals such as 5 dpf zebrafish. The developed EMG sensor and system are expected to become a helpful tool in validating zebrafish MD models and further developing therapeutics.

Thyroid status and cognitive function in euthyroid patients with early Parkinson's disease

BACKGROUND

Alterations in thyroid hormone (TH) levels may be related to the pathogenesis of mild cognitive impairment (MCI) and dementia. Cognitive deficits are common in Parkinson's disease (PD) patients. The aim of this study was to investigate whether variations within the normal ranges of thyroid function are related to cognitive function in early PD without dementia.

METHODS

Eighty-four euthyroid patients with early PD underwent evaluation of their thyroid status, including measures of thyroid-stimulating hormone (TSH), total triiodothyronine (tT3) and free thyroxine (fT4), and comprehensive neuropsychological tests.

RESULTS

The 46 patients of the PD-MCI group did not differ in the serum levels of TH compared to the 38 patients of the PD-normal cognition group. fT4 levels were inversely associated with the Mini-Mental State Examination (MMSE) score and neuropsychological tests of attention and visuospatial and executive function. TSH and tT3 levels were not related to cognitive performances. After controlling for demographic and clinical variables, multiple regression analyses indicated statistically significant associations between fT4 concentrations and MMSE score and neuropsychological tests of executive function.

CONCLUSIONS

This study supports a relationship between the thyroid status and cognitive function in euthyroid early PD patients, with higher concentrations of fT4 being associated with a poor performance of executive function.

Comparison of the Brain Volume in Essential Tremor and Parkinson's Disease Tremor Using an Automated Segmentation Method

BACKGROUND

Essential tremor (ET) and Parkinson's disease (PD) are common neurological disorders in elderly people, and some features of ET and PD may overlap. Quantitative analysis of brain atrophy may be useful in differentiating neurodegenerative disorders. The aim of this study was to identify the volumetric differences of subcortical structures in patients with ET and PD tremor using an automated segmentation method.

METHODS

Volumetric MRIs were obtained in 45 patients with ET, 45 patients with PD tremor, and 45 age- and sex-matched control subjects. The volume of the different brain structures was measured by the automated segmentation method (FreeSurfer).

RESULTS

Volumetric data obtained with automated segmentation of cerebral regions showed a significant atrophy of the cerebellum in patients with ET. Cerebellar atrophy of ET patients was more significant in the white matter than in the grey matter, and it was noted only in patients with ET having a head tremor. No volumetric differences were found between the PD group and the control group.

CONCLUSION

Our study suggests that volumetric differences in subcortical structures using whole brain segmentation method may help to differentiate ET from PD tremor.

Aspirin resistance in the acute stages of acute ischemic stroke is associated with the development of new ischemic lesions

BACKGROUND

Aspirin is a primary antiplatelet agent for the secondary prevention of ischemic stroke. However, if aspirin fails to inhibit platelet function, as is expected in acute ischemic stroke (AIS), it may increase the rate of early clinical events. Therefore, we sought to determine whether aspirin resistance in the acute stage was associated with early radiological events, including new ischemic lesions (NILs).

METHODS

This study was a single-center, prospective, observational study conducted between April 2012 and May 2013. Aspirin 300 mg was initially administered followed by maintenance doses of 100 mg daily. The acute aspirin reaction unit (aARU) was consistently measured after 3 hours of aspirin loading. An aARU value ≥550 IU was defined as biological aspirin resistance (BAR). NILs on follow-up diffusion-weighted imaging (DWI) were defined as lesions separate from index lesions, which were not detected on the initial DWI.

RESULTS

A total of 367 patients were analyzed in this study. BAR in aARU was detected in 60 patients (16.3%). On follow-up DWI, 81 patients (22.1%) had NILs, which were frequently in the same territory as the index lesions (79%), pial infarcts (61.7%), and located within the cortex (59.3%). BAR was independently associated with NILs on follow-up DWI (adjusted OR 2.00, 95% CIs 1.01-3.96; p = 0.047).

CONCLUSION

In conclusion, BAR in aARU could be associated with NILs on follow-up DWI in AIS. Therefore, a further prospective study with a longer follow-up period is necessary to evaluate the clinical implications of aARU in AIS.

Mutation analysis of SPAST, ATL1, and REEP1 in Korean Patients with Hereditary Spastic Paraplegia

Background and Purpose

Hereditary spastic paraplegia (HSP) is a genetically heterogeneous group of neurodegenerative disorders that are characterized by progressive spasticity and weakness of the lower limbs. Mutations in the spastin gene (SPAST) are the most common causes of HSP, accounting for 40-67% of autosomal dominant HSP (AD-HSP) and 12-18% of sporadic cases. Mutations in the atlastin-1 gene (ATL1) and receptor expression-enhancing protein 1 gene (REEP1) are the second and third most common causes of AD-HSP, respectively.

Methods

Direct sequence analysis was used to screen mutations in SPAST, ATL1, and REEP1 in 27 unrelated Korean patients with pure and complicated HSP. Multiplex ligation-dependent probe amplification was also performed to detect copy-number variations of the three genes.

Results

Ten different SPAST mutations were identified in 11 probands, of which the following 6 were novel: c.760A>T, c.131C>A, c.1351_1353delAGA, c.376_377dupTA, c.1114A>G, and c.1372A>C. Most patients with SPAST mutations had AD-HSP (10/11, 91%), and the frequency of SPAST mutations accounted for 66.7% (10/15) of the AD-HSP patients. No significant correlation was found between the presence of the SPAST mutation and any of the various clinical parameters of pure HSP. No ATL1 and REEP1 mutations were detected.

Conclusions

We conclude that SPAST mutations are responsible for most Korean cases of genetically confirmed AD-HSP. Our observation of the absence of ATL1 and REEP1 mutations needs to be confirmed in larger series.

Prevalence of anti-ganglioside antibodies and their clinical correlates with guillain-barré syndrome in Korea: a nationwide multicenter study

Background and Purpose

No previous studies have investigated the relationship between various anti-ganglioside antibodies and the clinical characteristics of Guillain-Barré syndrome (GBS) in Korea. The aim of this study was to determine the prevalence and types of anti-ganglioside antibodies in Korean GBS patients, and to identify their clinical significance.

Methods

Serum was collected from patients during the acute phase of GBS at 20 university-based hospitals in Korea. The clinical and laboratory findings were reviewed and compared with the detected types of anti-ganglioside antibody.

Results

Among 119 patients, 60 were positive for immunoglobulin G (IgG) or immunoglobulin M antibodies against any type of ganglioside (50%). The most frequent type was IgG anti-GM1 antibody (47%), followed by IgG anti-GT1a (38%), IgG anti-GD1a (25%), and IgG anti-GQ1b (8%) antibodies. Anti-GM1-antibody positivity was strongly correlated with the presence of preceding gastrointestinal infection, absence of sensory symptoms or signs, and absence of cranial nerve involvement. Patients with anti-GD1a antibody were younger, predominantly male, and had more facial nerve involvement than the antibody-negative group. Anti-GT1a-antibody positivity was more frequently associated with bulbar weakness and was highly associated with ophthalmoplegia when coupled with the coexisting anti-GQ1b antibody. Despite the presence of clinical features of acute motor axonal neuropathy (AMAN), 68% of anti-GM1- or anti-GD1a-antibody-positive cases of GBS were diagnosed with acute inflammatory demyelinating polyradiculoneuropathy (AIDP) by a single electrophysiological study.

Conclusions

Anti-ganglioside antibodies were frequently found in the serum of Korean GBS patients, and each antibody was correlated strongly with the various clinical manifestations. Nevertheless, without an anti-ganglioside antibody assay, in Korea AMAN is frequently misdiagnosed as AIDP by single electrophysiological studies.

Cross-cultural adaptation of the Korean version of the Boston carpal tunnel questionnaire: its clinical evaluation in patients with carpal tunnel syndrome following local corticosteroid injection

The aim of this study was to assess and validate the Korean version of the Boston Carpal Tunnel Questionnaire (K-BCTQ) in patients with carpal tunnel syndrome (CTS). After translation and cultural adaptation of the BCTQ to a Korean version, the K-BCTQ was administered to 54 patients with CTS; it was administered again after 2 weeks to assess reliability. Additionally, we administered K-DASH and EQ-5D to assess construct-validity. In a prospective study of responsiveness to clinical change, 29 of 54 patients were treated by ultrasonography-guided local corticosteroid injection therapy. The internal consistency of the K-BCTQ was high (Cronbach's alpha: 0.915) and the intra-class correlation coefficients were 0.931 for the symptom severity scale (P<0.001) and 0.844 for the functional severity scale (P<0.001). The construct-validity between the symptom severity scale and the K-DASH, and between the functional severity scale and the K-DASH were significantly correlated (both P<0.001). Clinical improvement was noted in 29 patients with injection therapy. The effect size of symptom severity was 0.67, and that of functional severity was 0.58. In conclusion, the K-BCTQ shows good reliability, construct-validity, and acceptable responsiveness after local corticosteroid injection therapy (Clinical trial number, KCT0000050).

Clinical characteristics and molecular genetic analysis of Korean patients with GNE myopathy

PURPOSE

Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is an autosomal recessive neuromuscular disorder characterized by early adult-onset weakness of the distal muscles of the lower limbs. The clinical spectrum of GNE myopathy varies, and it is not clear how the same GNE gene mutations can result in different phenotypes. Here, we present clinical, pathological and genetic characteristics of twenty-one Korean patients with GNE myopathy.

MATERIALS AND METHODS

Twenty-one GNE myopathy patients were included in this study, conducted from 2004 to 2011. Based on medical records, patients' gender, onset age, family history, clinical history, serum creatine kinase (CK) level, neurologic examination, findings of muscle biopsy, muscle imaging findings and electrophysiologic features were extensively reviewed. Mutation of the GNE gene (9p13.3) was confirmed by DNA direct sequencing analysis in all patients.

RESULTS

The mean onset age was 23.8±8.8 years (mean±SD). Patient serum CK levels were slightly to moderately elevated, ranging from 41 to 2610 IU. Among the patients, twelve patients were female and nine patients were male. Except for eight patients, all of the patients presented initially with only distal muscle weakness in the lower extremities. The most common mutation was V572L, followed by C13S.

CONCLUSION

The clinical manifestations of our patients with GNE mutations varied. Among twenty-one patients, thirteen patients showed the typical GNE myopathy phenotype. There was no relationship between clinical features and site of mutation. Therefore, we suggest that neither homozygous nor compound heterozygous models are correlated with disease phenotype or disease severity.

Hirayama disease presenting as isolated triceps atrophy

We describe an atypical case of Hirayama disease (HD) presenting as unilateral triceps atrophy. HD is juvenile muscular atrophy involving predominantly the seventh and eighth cervical, and the first thoracic spinal segments of the distal upper extremities. In contrast to typical HD, our patient presented with isolated triceps atrophy, innervated by the sixth and seventh cervical segments. We discuss the differences with previously reported HD and the mechanisms involved in the development of HD.

Mutation Screening of the γ-Aminobutyric Acid Type-A Receptor Subunit γ2 Gene in Korean Patients with Childhood Absence Epilepsy

Background and Purpose

Since the γ-aminobutyric acid type-A receptor subunit γ2 gene (GABRG2) mutation was discovered in an Australian family with childhood absence epilepsy (CAE) and febrile convulsions, a few screening studies for the GABRG2 mutation have been conducted in sporadic individuals with CAE from other ethnic groups. The aim of this study was to determine whether or not the previously reported genetic mutations and single-nucleotide polymorphisms (SNPs) of GABRG2 can be reproduced in sporadic Korean individuals with CAE, compared to healthy Korean individuals.

Methods

Thirty-five children with CAE in Chonnam National University Hospital and healthy controls (n=207) were enrolled, and the medical records of patients with CAE were reviewed. CAE was diagnosed according to the Classification and Terminology of the International League Against Epilepsy. All nine exons of GABRG2 were directly sequenced. In addition, the two SNPs found in our CAE patients were analyzed: C315T in exon 3 (E3) and C588T in exon 5 (E5). The frequencies of the two SNPs in the CAE patients were compared with data from healthy controls (for E3 and E5) and from previously reported Korean population data (only for E3).

Results

No mutation of GABRG2 was found in our CAE patients. In addition, the allele and genotype frequencies of the two polymorphisms did not differ significantly between CAE patients, healthy controls, and the Korean general population (p>0.05).

Conclusions

Our study of sporadic Korean individuals with CAE found no evidence that GABRG2 contributes to the genetic basis of CAE.