Mild Clinical Features and Histopathologically Atypical Cores in Two Korean Families with Central Core Disease Harboring RYR1 Mutations at the C-Terminal Region

Background

Central core disease (CCD) is a congenital myopathy characterized by distinctive cores in muscle fibers. Mutations in the gene encoding ryanodine receptor 1 (RYR1) have been identified in most CCD patients.

Case Report

Two unrelated patients presented with slowly progressive or nonprogressive proximal muscle weakness since childhood. Their family history revealed some members with the same clinical problem. Histological analysis of muscle biopsy samples revealed numerous peripheral cores in the muscle fibers. RYR1 sequence analysis disclosed a novel mutation in exon 101 (c.14590T>C) and confirmed a previously reported mutation in exon 102 (c.14678G>A).

Conclusions

We report herein two families with CCD in whom missense mutations at the C-terminal of RYR1 were identified. Although it has been accepted that such mutations are usually associated with a severe clinical phenotype and clearly demarcated central cores, our patients exhibited a mild clinical phenotype without facial muscle involvement and skeletal deformities, and atypical cores in their muscle biopsy specimens.

Weight changes in obese adults 6-months after discontinuation of double-blind zonisamide or placebo treatment

We evaluated weight changes in obese patients at 6-months after they ended participation in a 12-month randomised controlled trial in which they received daily placebo, zonisamide 200 mg or zonisamide 400 mg, in addition to lifestyle counselling. Of the originally randomised 225 patients, 218 completed month-12 when study interventions were discontinued. For the 154 patients who returned for 6-month follow-up off-treatment, weight changes between month-12 and month-18 for placebo (n = 53), zonisamide 200 mg (n = 49) and zonisamide 400 mg groups (n = 52) were 0.5 kg [95% confidence interval (CI), -0.8 to 1.8; 0.7%], 1.5 kg (0.2-2.8; 1.6%; p = 0.26 vs. placebo) and 2.4 kg (1.1-3.7; 2.6%; p = 0.04 vs. placebo), respectively. Our results suggest that although zonisamide 400 mg daily for 12-months resulted in greater weight loss than with placebo, weight regain after discontinuation of interventions was greater in the zonisamide 400 mg group than placebo group.

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.

A high-resolution whole-genome map of the distinctive epigenomic landscape induced by butyrate in bovine cells

This report presents a study utilizing next-generation sequencing technology, combined with chromatin immunoprecipitation (ChIP-seq) technology to analyze histone modification induced by butyrate and to construct a high-definition map of the epigenomic landscape with normal histone H3 and H4 and their variants in bovine cells at the whole-genome scale. A total of 10 variants of histone H3 and H4 modifications were mapped at the whole-genome scale (acetyl-H3K18-ChIP-seq, trimethy-H3K9, histone H4 ChIP-seq, acetyl-H4K5 ChIP-seq, acetyl-H4K12 ChIP-seq, acetyl-H4K16 ChIP-seq, histone H3 ChIP-seq, acetyl H3H9 ChIP-seq, acetyl H3K27 ChIP-seq and tetra-acetyl H4 ChIP-seq). Integrated experiential data and an analysis of histone and histone modification at a single base resolution across the entire genome are presented. We analyzed the enriched binding regions in the proximal promoter (within 5 kb upstream or at the 5'-untranslated region from the transcriptional start site (TSS)), and the exon, intron and intergenic regions (defined by regions 25 kb upstream and 10 kb downstream from the TSS). A de novo search for the binding motif of the 10 ChIP-seq datasets discovered numerous motifs from each of the ChIP-seq datasets. These consensus sequences indicated that histone modification at different locations changes the histone H3 and H4 binding preferences. Nevertheless, a high degree of conservation in histone binding also was presented in these motifs. This first extensive epigenomic landscape mapping in bovine cells offers a new framework and a great resource for testing the role of epigenomes in cell function and transcriptomic regulation.

Angiographic evaluation of hepatic arterial injury after cisplatin and Gelfoam-based transcatheter arterial chemoembolization for hepatocellular carcinoma in a 205 patient cohort during a 6-year follow-up

OBJECTIVE

To evaluate the overall and cumulative incidence, degree, interval change and predictors of hepatic arterial injury (HAI) after cisplatin and Gelfoam® (Upjohn, Kalamazoo, MI)-based transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).

METHODS

A total of 205 patients with HCC who underwent three or more sessions of TACE without additional surgical or local treatment were included. HAI was evaluated at each segment of the hepatic artery using a three-grade scale: 1 (slight wall irregularity), 2 (overt stenosis) and 3 (occlusion). HAI interval change was categorized into three groups: progression, stable state and improvement. Cumulative incidence of HAI was analysed using Kaplan- Meier method, and predictors of HAI (patient age, sex, portal vein thrombosis and Child-Pugh classification) were analysed by univariate logistic regression.

RESULTS

HAI occurred in 50 of the 205 study patients (24.4%). The cumulative incidence of HAI was 16.0% [95% confidence interval (CI), 10.21-21.77] during 5 sessions of TACE, 52.1% (95% CI, 37.83-66.29) during 10 sessions and 68.0% (95% CI, 67.62-88.46) during 15 sessions. Initial HAI was interpreted as grades 1, 2 and 3 in 11 (22.0%), 17 (34.0%) and 22 (44.0%) patients, respectively. When the interval change was assessed in 48 patients with available follow-up TACE, 40 (83.3%) were included in the progression, 2 (4.2%) in the stable state and 6 (12.5%) in the improvement groups. The univariate analysis used to determine the predictors of HAI revealed no significant predictors.

CONCLUSION

In three or more sessions of TACE, the incidence of HAI was 24%. Increasing TACE causes increased incidence of HAI. The initial presentation was most commonly grade 3, and 12.5% of the patients with HAI showed improvement of the HAI grade during follow-up TACE.

ADVANCES IN KNOWLEDGE

In patients who underwent three or more sessions of cisplatin and Gelfoam-based TACE, the overall incidence of HAI was 24.4%, and increasing TACE causes increased incidence of HAI.

Ahnak functions as a tumor suppressor via modulation of TGFβ/Smad signaling pathway

We provide detailed mechanisms of Ahnak-mediated potentiation of transforming growth factor β (TGFβ) signaling, which leads to a negative regulation of cell growth. We show that Smad3 interacts with Ahnak through MH2 domain and that Ahnak stimulates Smad3 localization into nucleus leading to potentiating TGFβ-induced transcriptional activity of R-Smad. Moreover, overexpression of Ahnak resulted in growth retardation and cell cycle arrest through downregulation of c-Myc and cyclin D1/D2. We describe results from analyses of Ahnak^−/− mouse model expressing middle T antigen in a mammary gland-specific manner (MMTV^Tg/+Ahnak^−/−), which showed significantly progressed hyperplasia of mammary glands compared with MMTV^Tg/+Ahnak^+/+. Finally, we screened multiple human breast cancer tissues and showed that the expression of Ahnak in cancer tissues is lower than that in control tissues by 50%. Taken together, these data indicate that Ahnak mediates a negative regulation of cell growth and acts as novel tumor suppressor through potentiation of TGFβ signaling.

Electrophysiological characteristics of six mutations in hClC-1 of Korean patients with myotonia congenita

ClC-1 is a member of a large family of voltage-gated chloride channels, abundantly expressed in human skeletal muscle. Mutations in ClC-1 are associated with myotonia congenita (MC) and result in loss of regulation of membrane excitability in skeletal muscle. We studied the electrophysiological characteristics of six mutants found among Korean MC patients, using patch clamp methods in HEK293 cells. Here, we found that the autosomal dominant mutants S189C and P480S displayed reduced chloride conductances compared to WT. Autosomal recessive mutant M128I did not show a typical rapid deactivation of Cl(-) currents. While sporadic mutant G523D displayed sustained activation of Cl(-) currents in the whole cell traces, the other sporadic mutants, M373L and M609K, demonstrated rapid deactivations. V1/2 of these mutants was shifted to more depolarizing potentials. In order to identify potential effects on gating processes, slow and fast gating was analyzed for each mutant. We show that slow gating of the mutants tends to be shifted toward more positive potentials in comparison to WT. Collectively, these six mutants found among Korean patients demonstrated modifications of channel gating behaviors and reduced chloride conductances that likely contribute to the physiologic changes of MC.

Stereotactic radiosurgery for metastatic spine tumors

Spinal metastases invariably affect the majority of patients with cancer. Many will develop symptoms related to pain and disability from epidural spinal cord compression as well as pathologic fracture of the vertebrae. With the emergence of targeted systemic therapies and a better understanding of cancer biology, patients are living longer with bony metastases. This poses particular challenges, as palliation of pain and maintenance of local tumor control are paramount to quality of life and overall functional independence for these patients. Stereotactic radiosurgery (SRS) has emerged as a potent primary standalone and adjuvant treatment option for spinal metastases. To date, the primary indications for SRS include 1) upfront standalone treatment for painful bony metastases in the oligometastatic patient, 2) standalone or post-operative treatment following progression or recurrence of local disease despite previous conventional external beam radiation therapy (cEBRT), and 3) following surgery during which epidural disease is decompressed and the spine stabilized when indicated. SRS has demonstrated a significant advantage over cEBRT for tumors traditionally regarded as relatively radioresistant such as sarcoma, melanoma, renal cell carcinoma, non-small cell lung cancer and colon carcinoma.9 The radiobiological advantage of increased tumoricidal dose delivery and spinal cord dose sparing in SRS have made this a powerful treatment alternative to cEBRT particularly within the context of re-irradiation. Given the limitations of spinal cord dose constraints, surgery is still the first-line therapy in patients with high-grade epidural spinal cord compression (ESCC). Epidural compression can be treated with SRS, however this risks radiation-induced myelopathy and challenges the safety of effective dose delivery at the dural margin.11 With increasing dose, radiation-induced vertebral fracture is the most serious and prevalent side effect of SRS.53 An overview of SRS, including the most common indications, complications, and outcomes for spinal metastases are presented here.

Characterization of 65 epitope-specific dystrophin monoclonal antibodies in canine and murine models of duchenne muscular dystrophy by immunostaining and western blot

Epitope-specific monoclonal antibodies can provide unique insights for studying cellular proteins. Dystrophin is one of the largest cytoskeleton proteins encoded by 79 exons. The absence of dystrophin results in Duchenne muscular dystrophy (DMD). Over the last two decades, dozens of exon-specific human dystrophin monoclonal antibodies have been developed and successfully used for DMD diagnosis. Unfortunately, the majority of these antibodies have not been thoroughly characterized in dystrophin-deficient dogs, an outstanding large animal model for translational research. To fill the gap, we performed a comprehensive study on 65 dystrophin monoclonal antibodies in normal and dystrophic dogs (heart and skeletal muscle) by immunofluorescence staining and western blot. For comparison, we also included striated muscles from normal BL10 and dystrophin-null mdx mice. Our analysis revealed distinctive species, tissue and assay-dependent recognition patterns of different antibodies. Importantly, we identified 15 antibodies that can consistently detect full-length canine dystrophin in both immunostaining and western blot. Our results will serve as an important reference for studying DMD in the canine model.

Clinical and Pathological Features of Korean Patients with DNM2-Related Centronuclear Myopathy

Background and Purpose

Centronuclear myopathy (CNM) is characterized by the presence of central nuclei within a large number of muscle fibers. Mutations of the dynamin 2 gene (DNM2) are common causes of autosomal dominant or sporadic CNM. The aim of this study was to characterize the clinical and pathological features of CNM relative to the presence of DNM2 mutations.

Methods

Six patients with clinical and pathological features of CNM were recruited. Detailed clinical and pathological findings were analyzed according to the presence of DNM2 mutations.

Results

We detected DNM2 mutations in four of the six sporadic CNM patients, and identified the following distinct clinical and pathological features in those patients with DNM2 mutations: preferential involvement of the distal lower limbs, typical nuclear centralization, and radially distributed sarcoplasmic strands in muscle pathology. In contrast, those without DNM2 mutations exhibited rather diffuse muscular involvement, and nuclear internalization and myofibrillar disorganization were more pronounced features of their muscle pathology.

Conclusions

These findings suggest the presence of specific features in Korean CNM patients. A detailed clinical and pathological examination of CNM patients would be helpful for molecular genetic analyses of this condition.

Identification of a novel HLA-B allele, B*46:39, by sequence-based typing

The new allele B*46:39 showed a single-nucleotide substitution compared with B*46:01 at codon 185 (CCA/ACA).

Mid-long term effect of non-ablative high radiofrequency therapy on the rabbit dermal extracellular matrix

This study quantitatively investigated the postoperative effects of radiofrequency (RF) application on the normal dermal extracellular matrix (ECM) of in vivo rabbits. Postoperative effects were evaluated by histology and atomic force microscopy analysis of dermal tissues treated using three RF energy levels (10 ~ 30 W) and either a single- or multiple-pass procedure. Progressive changes in the morphology of rabbit dermal ECMs were investigated over a 30-day postoperartive period. All RF-treated groups, except for the low energy group (10 W), displayed more prominent inflammatory responses compared to the control. This inflammatory reaction was more prominent a day after application. Dermal tissues 30 days after RF application exhibited prominent myofibroblast activity associated with ECM contractile activity during wound healing in addition to chronic inflammation. A decrease in the morphology of dermal ECMs after RF application continued until seven days postoperatively. The ECM diameter increased to near baseline at 30 days postoperatively. Low energy and multi-pass applications resulted in greater collagen fibril contraction and recovery at the ultra-structural level at 30 days postoperatively than did a single high energy application.

Fibrolytic enzyme and ammonia application effects on the nutritive value, intake, and digestion kinetics of bermudagrass hay in beef cattle

The objectives were to compare the effect of exogenous fibrolytic enzyme (Biocellulase A20) or anhydrous ammonia (4% DM) treatment on the nutritive value, voluntary intake, and digestion kinetics of bermudagrass (Cynodon dactylon cultivar Coastal) hay harvested after 2 maturities (5- and 13-wk regrowths). Six individually housed, ruminally cannulated Brangus steers (BW 325 ± 10 kg) were used in an experiment with a 6 × 6 Latin square design with a 3 (additives) × 2 (maturities) factorial arrangement of treatments. Each period consisted of 14 d of adaptation and 7, 4, 1, 1, and 4 d for measuring in vivo digestibility, in situ degradability, no measurements, rumen liquid fermentation and passage indices, and rate of solid passage, respectively. Steers were fed hay for ad libitum intake and supplemented with sugarcane molasses and distillers grain (supplement total of 2.88 kg DM/d). Enzyme did not affect the nutritional composition of hay but ammonia treatment decreased hay NDF, hemicellulose, and ADL concentrations and increased the CP concentration particularly for the mature lignified 13-wk hay. The enzyme increased NDF and hemicellulose digestibility of the 5-wk hay but decreased those of the 13-wk hay. Ammoniation decreased intake of hay but increased digestibility of DM, OM, NDF, hemicellulose, ADF, and cellulose and increased the ruminal in situ soluble and potentially digestible fractions and the rate of DM degradation of the 13-wk hay. Also, ammoniation increased the concentrations of ruminal NH3, total VFA, acetate, and butyrate but enzyme treatment did not. Neither enzyme addition nor ammoniation affected rate of liquid and solid passage. In conclusion, ammoniation decreased the concentration of most fiber fractions, decreased the intake of hays, and increased their CP concentration, in vivo digestibility, and in situ degradability at both maturities whereas enzyme application increased fiber digestibility of the 5-wk hay but decreased it in the case of the 13-wk hay.

Optimized cutoff value and indication for washout thyroglobulin level according to ultrasound findings in patients with well-differentiated thyroid cancer

BACKGROUND AND PURPOSE

Washout thyroglobulin provides evidence for metastatic or recurrent lesions, However, the cutoff value is still controversial. We investigated an optimized cutoff value and indication for the use of washout thyroglobulin from fine-needle aspiration in neck lymph nodes from preoperative or postoperative patients with well-differentiated thyroid cancers.

MATERIALS AND METHODS

A total of 177 lymph nodes from 161 patients underwent sonographically guided fine-needle aspiration cytology and washout thyroglobulin measurement and then underwent surgery and clinical follow-up. We assessed an optimized cutoff value of washout thyroglobulin for diagnosing metastasis and compared its diagnostic performance with that of washout thyroglobulin > 10 ng/mL, the currently accepted cutoff value. We also analyzed diagnostic performances of fine-needle aspiration cytology alone and of the combination of fine-needle aspiration cytology and washout thyroglobulin on the basis of the presence or absence of suspicious ultrasonographic findings.

RESULTS

Of the 177 lymph nodes, 77 were metastases and 100 were benign. An optimized cutoff value for washout thyroglobulin was 1.8 ng/mL. The sensitivity and negative predictive value in diagnosing metastasis improved significantly with a cutoff value of 1.8 ng/mL compared with a cutoff value of 10 ng/mL (P = .0412 for sensitivity, P = .0188 for negative predictive value). In patients with suspicious ultrasonographic findings, applying washout thyroglobulin along with fine-needle aspiration cytology significantly enhanced the sensitivity and negative predictive value of fine-needle aspiration cytology performances to 100% and 100%, respectively (P = .0051, and P = .0088). There was no difference in diagnostic performance between fine-needle aspiration cytology and the combination of the 2 methods in patients without suspicious ultrasonographic findings.

CONCLUSIONS

Applying the optimized cutoff value of washout thyroglobulin of 1.8 ng/mL in patients with suspicious ultrasonographic features facilitates the diagnostic evaluation of neck lymph nodes in both preoperative and postoperative patients with well-differentiated thyroid cancer.

Long-term robust myocardial transduction of the dog heart from a peripheral vein by adeno-associated virus serotype-8

Molecular intervention using noninvasive myocardial gene transfer holds great promise for treating heart diseases. Robust cardiac transduction from peripheral vein injection has been achieved in rodents using adeno-associated virus (AAV) serotype-9 (AAV-9). However, a similar approach has failed to transduce the heart in dogs, a commonly used large animal model for heart diseases. To develop an effective noninvasive method to deliver exogenous genes to the dog heart, we employed an AAV-8 vector that expresses human placental alkaline phosphatase reporter gene under the transcriptional regulation of the Rous sarcoma virus promoter. Vectors were delivered to three neonatal dogs at the doses of 1.35×10(14), 7.14×10(14), and 9.06×10(14) viral genome particles/kg body weight via the jugular vein. Transduction efficiency and overall safety were evaluated at 1.5, 2.5, and 12 months postinjection. AAV delivery was well tolerated and dog growth was normal. Blood chemistry and internal organ histology were unremarkable. Widespread skeletal muscle transduction was observed in all dogs without T-cell infiltration. Encouragingly, whole heart myocardial transduction was achieved in two dogs that received higher doses and cardiac expression lasted for at least 1 year. In summary, peripheral vein AAV-8 injection may represent a simple heart gene transfer method in large mammals. Further optimization of this gene delivery strategy may open the door for a readily applicable gene therapy method to treat many heart diseases.

Multidisciplinary approach in the management of a complicated crown root fracture

BACKGROUND

This article describes the management of a complicated crown root fracture.

CASE REPORT

A young patient presented with a crown root fracture of the maxillary left central incisor with an oblique subgingival fracture line. A multidisciplinary treatment approach including endodontic treatment, orthodontic extrusion, surgical extraction and intra-alveolar repositioning was used to gain sufficient crown length of the fractured maxillary incisor. The coronally repositioned maxillary left central incisor was stabilised by sutures and a resin wire splint. A resin core was built up followed by fabrication of an all-ceramic crown. Clinical and radiographic follow-up of the maxillary left central incisor after 24 months showed no signs of bone resorption or pathology and good aesthetics and functions were maintained.

Ultrasonography-guided core needle biopsy for the thyroid nodule: does the procedure hold any benefit for the diagnosis when fine-needle aspiration cytology analysis shows inconclusive results?

OBJECTIVE

We evaluated the diagnostic role of ultrasonography-guided core needle biopsy (CNB) according to ultrasonography features of thyroid nodules that had inconclusive ultrasonography-guided fine-needle aspiration (FNA) results.

METHODS

A total of 88 thyroid nodules in 88 patients who underwent ultrasonography-guided CNB because of previous inconclusive FNA results were evaluated. The patients were classified into three groups based on ultrasonography findings: Group A, which was suspicious for papillary thyroid carcinoma (PTC); Group B, which was suspicious for follicular (Hurthle cell) neoplasm; and Group C, which was suspicious for lymphoma. The final diagnoses of the thyroid nodules were determined by surgical confirmation or follow-up after ultrasonography-guided CNB.

RESULTS

Of the 88 nodules, the malignant rate was 49.1% in Group A, 12.0% in Group B and 90.0% in Group C. The rates of conclusive ultrasonography-guided CNB results after previous incomplete ultrasonography-guided FNA results were 96.2% in Group A, 64.0% in Group B and 90.0% in Group C (p=0.001). 12 cases with inconclusive ultrasonography-guided CNB results were finally diagnosed as 8 benign lesions, 3 PTCs and 1 lymphoma. The number of previous ultrasonography-guided FNA biopsies was not significantly different between the conclusive and the inconclusive result groups of ultrasonography-guided CNB (p=0.205).

CONCLUSION

Ultrasonography-guided CNB has benefit for the diagnosis of thyroid nodules with inconclusive ultrasonography-guided FNA results. However, it is still not helpful for the differential diagnosis in 36% of nodules that are suspicious for follicular neoplasm seen on ultrasonography.

ADVANCES IN KNOWLEDGE

This study shows the diagnostic contribution of ultrasonography-guided CNB as an alternative to repeat ultrasonography-guided FNA or surgery.

Quantitative phenotyping of Duchenne muscular dystrophy dogs by comprehensive gait analysis and overnight activity monitoring

The dystrophin-deficient dog is excellent large animal model for testing novel therapeutic modalities for Duchenne muscular dystrophy (DMD). Despite well-documented descriptions of dystrophic symptoms in these dogs, very few quantitative studies have been performed. Here, we developed a comprehensive set of non-invasive assays to quantify dog gait (stride length and speed), joint angle and limb mobility (for both forelimb and hind limb), and spontaneous activity at night. To validate these assays, we examined three 8-m-old mix-breed dystrophic dogs. We also included three age-matched siblings as the normal control. High-resolution video recorders were used to digitize dog walking and spontaneous movement at night. Stride speed and length were significantly decreased in affected dogs. The mobility of the limb segments (forearm, front foot, lower thigh, rear foot) and the carpus and hock joints was significantly reduced in dystrophic dogs. There was also a significant reduction of the movement in affected dogs during overnight monitoring. In summary, we have established a comprehensive set of outcome measures for clinical phenotyping of DMD dogs. These non-invasive end points would be valuable in monitoring disease progression and therapeutic efficacy in translational studies in the DMD dog model.

Possible anticipation associated with a novel splice site mutation in episodic ataxia type 2

Anticipation is a phenomenon characterized by decreasing age at onset and increasing severity of symptoms of a disease in successive generations within a pedigree. Anticipation mostly occurs in neurodegenerative diseases with expansion of unstable trinucleotide repeats. However, it has not been previously pointed out in episodic ataxia type 2 (EA2). Clinical and genetic analyses were performed in nine members from three consecutive generations of a Korean family with EA2. We performed a polymerase chain reaction (PCR)-based direct sequence analysis of all coding regions of CACNA1A using genomic DNA. The clinically affected family members showed recurrent vertigo, interictal nystagmus, and childhood epilepsy. There is a decrease in the age onset (possible genetic anticipation) in three succeeding generations of the family. Genetic analysis identified a splice site mutation (p.Val1465Glyfs13X) and normal trinucleotide repeats in CACNA1A in all clinically affected and one unaffected members. Recognizing anticipation would aid in genetic counseling in EA2.

Effects of feeding crude glycerin on performance and ruminal kinetics of lactating Holstein cows fed corn silage- or cottonseed hull-based, low-fiber diets

The objective was to determine whether crude glycerin could partially replace concentrate ingredients in corn silage- or cottonseed hull-based diets formulated to support minimal milk fat production without reducing milk production. Multiparous, lactating Holstein cows (n=24; 116 ± 13d in milk) were assigned to dietary treatments arranged in a 2 × 3 factorial design; namely, 2 dietary roughage sources (cottonseed hulls or corn silage) and 3 dietary concentrations of glycerin [0, 5, or 10% on a dry matter (DM) basis]. Four different cows received each dietary treatment in each of 3 periods such that each diet was evaluated using 12 cows. Crude glycerin, produced using soybean oil, contained 12% water, 5% oil, 6.8% sodium chloride, and 0.4% methanol. Glycerin partially replaced ground corn, corn gluten feed, and citrus pulp. Diets of minimum fiber concentrations were fed to lactating dairy cows and resulted in low concentrations of milk fat (averaging 3.12% for cows fed diets without glycerin). The effects of glycerin on cow performance and ruminal measurements were the same for both dietary roughage sources with the exception of feed efficiency. Replacing concentrate with crude glycerin at 5% of dietary DM increased DM intake without increasing milk yield. Concentration and yield of milk fat were reduced when glycerin was fed at 10% of dietary DM. This was accompanied by a 30% reduction in apparent total-tract digestion of dietary neutral detergent fiber. Crude glycerin affected the microbial population in the rumen as evidenced by increased molar proportions of propionic, butyric, and valeric acids and decreased molar proportions of acetic acid. Efficiency of N utilization was improved as evidenced by lower concentrations of blood urea nitrogen and ruminal ammonia-N. Cows fed cottonseed hull-based diets consumed 5.3 kg/d more DM but produced only 1.7 kg/d more milk, resulting in reduced efficiency. Increased production of ruminal microbial protein, molar proportion of propionic acid, and passage of ruminal fluid resulted from feeding the cottonseed hull- versus corn silage-based diets, although apparent digestibilities of DM and neutral detergent fiber were reduced. Replacing 5 and 10% of concentrate ingredients with crude glycerin improved efficiency of 4% fat-corrected milk production when corn silage-based diets were fed but decreased it when cottonseed hull-based diets were fed.

Limb-girdle phenotype is frequent in patients with myopathy associated with GNE mutations

The gene GNE encodes a bifunctional enzyme, UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase. Its mutations are found in distal myopathy with rimmed vacuoles (DMRV) and hereditary inclusion body myopathy (HIBM). Those disorders are characterized clinically by predominant anterior tibial muscle weakness and atrophy, and pathologically by rimmed vacuoles on muscle biopsy. We analyzed 11 Korean patients with GNE mutations. The mutations showed ethnic similarity to those of Japanese patients, showing the highest frequency with V572L. Another mutation of C13S was also found recurring in our patient group. Interestingly, about half of the patients showed limb-girdle myopathy rather than distal myopathy. This was further represented by limb muscle CT scans revealing atrophic hamstring and relatively spared anterior tibial muscle. However, quadriceps muscles were consistently spared both in distal and limb-girdle phenotypes. In conclusion, this study demonstrates a phenotypic diversity associated with GNE mutations. Recognizing a wider clinical spectrum of GNE mutations will help benefit more patients with imminent new therapy.

Primary anaplastic lymphoma kinase-negative anaplastic large-cell lymphoma of the breast in a male patient

Anaplastic large-cell lymphoma is an extremely rare lymphoma subtype. We describe the mammographic and ultrasonographic findings in a 51-year-old male patient who suffered from a palpable lump caused by this rare disease.

AAV micro-dystrophin gene therapy alleviates stress-induced cardiac death but not myocardial fibrosis in >21-m-old mdx mice, an end-stage model of Duchenne muscular dystrophy cardiomyopathy

Duchenne muscular dystrophy (DMD) is a fatal genetic disease caused by the absence of the sarcolemmal protein dystrophin. Dilated cardiomyopathy leading to heart failure is a significant source of morbidity and mortality in DMD. We recently demonstrated amelioration of DMD heart disease in 16 to 20-m-old dystrophin-null mdx mice using adeno-associated virus (AAV) mediated micro-dystrophin gene therapy. DMD patients show severe heart disease near the end of their life expectancy. Similarly, mdx mice exhibit profoundly worsening heart disease when they reach beyond 21 months of age. To more rigorously test micro-dystrophin therapy, we treated mdx mice that were between 21.2 and 22.7-m-old (average, 22.1 ± 0.2 months; N=8). The ∆R4-23/∆C micro-dystrophin gene was packaged in the cardiotropic AAV-9 virus. 5×10(12) viral genome particles/mouse were delivered to mdx mice via the tail vein. AAV transduction, myocardial fibrosis and heart function were examined 1.7 ± 0.2 months after gene therapy. Efficient micro-dystrophin expression was observed in the myocardium of treated mice. Despite the robust dystrophin expression, myocardial fibrosis was not mitigated. Most hemodynamic parameters were not improved either. However, ECG abnormalities were partially corrected. Importantly, treated mice became more resistant to dobutamine-induced cardiac death. In summary, we have revealed for the first time the potential benefits and limitations of AAV micro-dystrophin therapy in end-stage Duchenne dilated cardiomyopathy. Our findings have important implications for the use of AAV gene therapy in dilated cardiomyopathy and heart failure.

Humoral immunity to AAV-6, 8, and 9 in normal and dystrophic dogs

Adeno-associated virus (AAV)-6, 8, and 9 are promising gene-delivery vectors for testing novel Duchenne muscular dystrophy gene therapy in the canine model. Humoral immunity greatly influences in vivo AAV transduction. However, neutralizing antibodies to AAV-6, 8, and 9 have not been systemically examined in normal and dystrophic dogs. To gain information on the seroprevalence of antibodies to AAV-6, 8, and 9, we measured neutralizing antibody titers using an in vitro transduction inhibition assay. We examined 72 naive serum samples and 26 serum samples obtained from dogs that had received AAV gene transfer. Our data demonstrated that AAV-6 neutralizing antibody was the most prevalent antibody in dogs irrespective of age, gender, disease status (dystrophic or not), and prior parvovirus vaccination history. Surprisingly, high-level anti-AAV-6 antibody was detected at birth in newborn puppies. Further, a robust antibody response was induced in affected, but not normal newborn dogs following systemic AAV gene transfer. Taken together, our data have provided an important baseline on the seroprevalence of AAV-6, 8, and 9 neutralizing antibodies in normal and Duchenne muscular dystrophy dogs. These results will help guide translational AAV gene-therapy studies in dog models of muscular dystrophy.

Recombinant adeno-associated viral vector production and purification

Gene delivery vectors based on recombinant adeno-associated virus (AAV) are powerful tools for studying myogenesis in normal and diseased conditions. Strategies have been developed to use AAV to increase, down-regulate, or modify expression of a particular muscle gene in a specific muscle, muscle group(s), or all muscles in the body. AAV-based muscle gene therapy has been shown to cure several inherited muscle diseases in animal models. Early clinical trials have also yielded promising results. In general, AAV vectors lead to robust, long-term in vivo transduction in rodents, dogs, and non-human primates. To meet specific research needs, investigators have developed numerous AAV variants by engineering viral capsid and/or genome. Here we outline a generic AAV production and purification protocol. Techniques described here are applicable to any AAV variant.

A simplified immune suppression scheme leads to persistent micro-dystrophin expression in Duchenne muscular dystrophy dogs

Highly abbreviated micro-dystrophin genes have been intensively studied for Duchenne muscular dystrophy (DMD) gene therapy. Following adeno-associated virus (AAV) gene transfer, robust microgene expression is achieved in murine DMD models in the absence of immune suppression. Interestingly, a recent study suggests that AAV gene transfer in dystrophic dogs may require up to 18 weeks' immune suppression using a combination of three different immune-suppressive drugs (cyclosporine, mycophenolate mofetil, and anti-dog thymocyte globulin). Continued immune suppression is not only costly but also may cause untoward reactions. Further, some of the drugs (such as anti-dog thymocyte globulin) are not readily available. To overcome these limitations, we developed a novel 5-week immune suppression scheme using only cyclosporine and mycophenolate mofetil. AAV vectors (either AV.RSV.AP that expresses the heat-resistant human alkaline phosphatase gene, or AV.CMV.μDys that expresses the canine R16-17/H3/ΔC microgene) at 2.85×10(12) vg particles were injected into adult dystrophic dog limb muscles under the new immune suppression protocol. Sustained transduction was observed for nearly half year (the end of the study). The simplified immune suppression strategy described here may facilitate preclinical studies in the dog model.

The evolution of heart gene delivery vectors

Gene therapy holds promise for treating numerous heart diseases. A key premise for the success of cardiac gene therapy is the development of powerful gene transfer vehicles that can achieve highly efficient and persistent gene transfer specifically in the heart. Other features of an ideal vector include negligible toxicity, minimal immunogenicity and easy manufacturing. Rapid progress in the fields of molecular biology and virology has offered great opportunities to engineer various genetic materials for heart gene delivery. Several nonviral vectors (e.g. naked plasmids, plasmid lipid/polymer complexes and oligonucleotides) have been tested. Commonly used viral vectors include lentivirus, adenovirus and adeno-associated virus. Among these, adeno-associated virus has shown many attractive features for pre-clinical experimentation in animal models of heart diseases. We review the history and evolution of these vectors for heart gene transfer.

Rupture of benign thyroid tumors after radio-frequency ablation

Rupture of benign thyroid tumors after RFA is very rare. We experienced 6 cases in 4 institutions. All patients presented with abrupt neck swelling and pain between 9 and 60 days after RFA. Imaging and clinical findings of the ruptured tumors were anterior subcapsular location, mixed composition, large size, and repeated ablations. Conservative treatment was sufficient in 3 cases, whereas surgical management was required in 3.

Stereotactic radiosurgery for spinal metastases: update on treatment strategies

Metastatic tumors are the most common tumors that affect the spinal column and are the source of significant pain and disability in cancer patients. The management of symptomatic spinal metastases presents unique challenges to surgeons as a number of considerations specific to the underlying tumor histology, extent of disease, the functional status of the patient and response to systemic therapy often affect the role, timing and effectiveness of any surgical intervention. As surgical techniques have evolved, the focus of therapy has shifted towards minimizing the morbidity associated with treatments for patients in whom limited nutrition and functional reserve impact their overall survival. As such, stereotactic spinal radiosurgery (SRS) has emerged as a powerful adjunct to surgery as well as a stand-alone treatment option for patients with metastatic disease. Recent technological innovations such as intensity-modulated radiation therapy, image-guidance, and non-invasive spine immobilization have made significant improvements to the delivery of highly conformal radiation to spinal tumors. In this article, current treatment strategies utilizing SRS in the multidisciplinary management of spinal metastases are discussed.

SERCA2a gene transfer improves electrocardiographic performance in aged mdx mice

Background

Cardiomyocyte calcium overloading has been implicated in the pathogenesis of Duchenne muscular dystrophy (DMD) heart disease. The cardiac isoform of sarcoplasmic reticulum calcium ATPase (SERCA2a) plays a major role in removing cytosolic calcium during heart muscle relaxation. Here, we tested the hypothesis that SERCA2a over-expression may mitigate electrocardiography (ECG) abnormalities in old female mdx mice, a murine model of DMD cardiomyopathy.

Methods

1 × 10¹² viral genome particles/mouse of adeno-associated virus serotype-9 (AAV-9) SERCA2a vector was delivered to 12-m-old female mdx mice (N = 5) via a single bolus tail vein injection. AAV transduction and the ECG profile were examined eight months later.

Results

The vector genome was detected in the hearts of all AAV-injected mdx mice. Immunofluorescence staining and western blot confirmed SERCA2a over-expression in the mdx heart. Untreated mdx mice showed characteristic tachycardia, PR interval reduction and QT interval prolongation. AAV-9 SERCA2a treatment corrected these ECG abnormalities.

Conclusions

Our results suggest that AAV SERCA2a therapy may hold great promise in treating dystrophin-deficient heart disease.

AAV-microdystrophin therapy improves cardiac performance in aged female mdx mice

Dystrophin deficiency leads to lethal dilated Duchenne cardiomyopathy. A promising therapy is to deliver a highly abbreviated microdystrophin gene to the heart using adeno-associated virus (AAV). Microdystrophin has been shown to mitigate dystrophin-deficient skeletal muscle disease. However, it is not clear whether microdystrophin is equally effective in treating Duchenne cardiomyopathy. To evaluate microdystrophin therapy in the heart, we injected 5 × 10(12) viral genome particles/mouse of AAV-9 ΔR4-23/ΔC microdystrophin vector via tail vein to ~16-20-month-old (average 18.7-month-old) female mdx mice, a manifesting model of Duchenne cardiomyopathy. Cardiac transduction and heart function were examined at 2-8 months after gene transfer. We observed robust myocardial microdystrophin expression. Electrocardiography (ECG) and left ventricular catheter hemodynamic assays also revealed significant improvement. Furthermore, AAV-microdystrophin therapy prevented dobutamine-stress induced acute cardiac death. We demonstrate for the first time that AAV microdystrophin therapy significantly ameliorates functional deficiency in a phenotypic model of Duchenne cardiomyopathy. Our results support further exploration of microdystrophin therapy to treat Duchenne cardiomyopathy.

Diagnostic dilemmas of hyalinizing trabecular tumours on fine needle aspiration cytology: a study of seven cases with BRAF mutation analysis

OBJECTIVE

Hyalinizing trabecular tumours (HTTs) are rare follicular-derived neoplasms that behave in an almost benign manner. HTT is frequently misdiagnosed as papillary carcinoma by fine needle aspiration (FNA) cytology or as papillary or medullary carcinoma on surgical resection.

METHODS

The authors examined FNA material from seven cases of histologically verified HTT. Cytological findings were reviewed and correlated with ultrasonographic and histological features. In addition, MIB-1 and calcitonin immunostaining was performed on surgical specimens, and BRAF mutation analysis on three pre-operative FNA specimens and seven histology specimens.

RESULTS

The original cytological diagnosis was either suspicious or positive for papillary carcinoma in all patients. The FNA-based differential diagnoses included HTT, papillary carcinoma or, less likely, medullary carcinoma in two patients. Aspirates showed oval to spindle-shaped cells with frequent intranuclear inclusions, isolated in loosely cohesive groups with a trabecular or syncytial pattern in a bloody background. Radiating arrangements of tumour cells surrounding hyaline stroma with serrated calcifications and a lack of papillary or sheet-like fragments may suggest HTT on FNA. Spherical calcified bodies and possible psammoma bodies were frequently found in three cases. Retrospectively, six of the seven cases showed membranous immunoreactivity for MIB-1, but none of the seven possessed the BRAF (V600E) mutation or showed calcitonin reactivity.

CONCLUSIONS

Although the recognition of HTT on FNA cytology is difficult, because of its morphological similarities to papillary and medullary carcinoma, its characteristic cytological features along with ultrasonographic findings may suggest the diagnosis preoperatively and avoid surgical over-treatment.

Age-matched comparison reveals early electrocardiography and echocardiography changes in dystrophin-deficient dogs

The absence of dystrophin in the heart leads to Duchenne cardiomyopathy. Dystrophin-deficient dogs represent a critical model to translate novel therapies developed in mice to humans. Unfortunately, little is known about cardiophysiology changes in these dogs. We performed prospective electrocardiographic and echocardiographic examinations at 3, 6 and 12 months of age in four normal and three affected dogs obtained from the same litter. Affected dogs showed growth retardation and serum creatine kinase elevation. Necropsy confirmed cardiac dystrophin deficiency and histopathology. Q/R ratio elevation and diastolic left ventricular (LV) internal diameter reduction were the most consistent findings in affected dogs at all ages. At 6 and 12 months, dystrophic dogs also showed significant reduction of PR intervals, LV end diastolic/systolic volumes and systolic LV internal diameters. Epicardial and endocardial slope times were significantly reduced in affected dogs at 12 months. These results establish the baseline for evaluating experimental therapies in the future.

iNOS ablation does not improve specific force of the extensor digitorum longus muscle in dystrophin-deficient mdx4cv mice

Nitrosative stress compromises force generation in Duchenne muscular dystrophy (DMD). Both inducible nitric oxide synthase (iNOS) and delocalized neuronal NOS (nNOS) have been implicated. We recently demonstrated that genetic elimination of nNOS significantly enhanced specific muscle forces of the extensor digitorum longus (EDL) muscle of dystrophin-null mdx4cv mice (Li D et al J. Path. 223:88-98, 2011). To determine the contribution of iNOS, we generated iNOS deficient mdx4cv mice. Genetic elimination of iNOS did not alter muscle histopathology. Further, the EDL muscle of iNOS/dystrophin DKO mice yielded specific twitch and tetanic forces similar to those of mdx4cv mice. Additional studies suggest iNOS ablation did not augment nNOS expression neither did it result in appreciable change of nitrosative stress markers in muscle. Our results suggest that iNOS may play a minor role in mediating nitrosative stress-associated force reduction in DMD.

Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model

OBJECTIVE

Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility.

METHODS

A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8).

RESULTS

The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01).

CONCLUSION

Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent.

Connectional parameters determine multisensory processing in a spiking network model of multisensory convergence

For the brain to synthesize information from different sensory modalities, connections from different sensory systems must converge onto individual neurons. However, despite being the definitive, first step in the multisensory process, little is known about multisensory convergence at the neuronal level. This lack of knowledge may be due to the difficulty for biological experiments to manipulate and test the connectional parameters that define convergence. Therefore, the present study used a computational network of spiking neurons to measure the influence of convergence from two separate projection areas on the responses of neurons in a convergent area. Systematic changes in the proportion of extrinsic projections, the proportion of intrinsic connections, or the amount of local inhibitory contacts affected the multisensory properties of neurons in the convergent area by influencing (1) the proportion of multisensory neurons generated, (2) the proportion of neurons that generate integrated multisensory responses, and (3) the magnitude of multisensory integration. These simulations provide insight into the connectional parameters of convergence that contribute to the generation of populations of multisensory neurons in different neural regions as well as indicate that the simple effect of multisensory convergence is sufficient to generate multisensory properties like those of biological multisensory neurons.

Adeno-associated virus serotype 6 capsid tyrosine-to-phenylalanine mutations improve gene transfer to skeletal muscle

Adeno-associated viral (AAV) vectors are the most efficient in vivo gene transfer tools for gene therapy applications. Efforts have been made to translate encouraging results in small animal models to human patients. However, the need for large quantities of vector for clinical application remains a great challenge. Developing novel AAV vectors with enhanced infectivity may reduce the high vector dose requirement for many applications such as gene therapy for muscular dystrophy. Selective mutation of AAV capsid surface-exposed tyrosine (Y) is a novel strategy to improve transduction efficiency. AAV6 has been considered one of the most robust muscle gene delivery vehicles. Here, we hypothesize that AAV6 transduction efficiency can be further enhanced by mutating surface Y to phenylalanine (F). We found that mutants AAV6-Y445F and AAV6-Y731F, especially the former, achieved more efficient gene transfer than the original AAV6 after intramuscular administration to mice. Expression of both firefly luciferase and alkaline phosphatase reporter genes increased up to 8-fold and DNA copy numbers in muscle increased up to 6-fold. Our results suggest that tyrosine-mutant AAV6 vectors may represent powerful tools for testing muscle gene therapy in animal models and potentially in humans.

Experimental lung collapse following deployment of a self-expandable bronchial occluder in a rabbit model

OBJECTIVES

Closure of a bronchopleural fistula is required to prevent fatal empyema or aspiration pneumonia. The purpose of this study was to determine the feasibility and efficacy of bronchial occlusion with a self-expandable occluder to induce experimental lung collapse in a rabbit model.

METHODS

10 bronchial occluders (wine glass appearance; 8 mm in diameter and 15 mm in length) were implanted in the native left main bronchi of 10 rabbits via an endotracheal route. We analysed the following: (1) diameters and morphological changes of the bronchial occluders during follow-up; (2) percentage volume of the collapsed lung during follow-up; and (3) complications and gross pathology. 1-day and 2-week follow-up CT scans were routinely obtained. Rabbits were sacrificed 4 weeks after the experiment.

RESULTS

In all 10 rabbits, the bronchial occluders were successfully implanted and were completely expanded within 2 weeks. Complete collapse of the left lung occurred in three rabbits on day 1 and in an additional two rabbits 2 weeks following implantation. Two other rabbits maintained the percentage volume of the collapsed lung between 51% and 99% during follow-up; the other three rabbits had <50% during follow-up. Pneumothoraces occurred in nine rabbits, but completely resolved at the 2-week follow-up. Right lung herniation across the midline progressed 2 weeks after occluder implantation.

CONCLUSION

Placement of self-expandable occluders in a rabbit bronchus model was feasible and showed a potential to induce artificial lung collapse. While pneumothoraces were common, they resolved during follow-up.

Genotyping mdx, mdx3cv, and mdx4cv mice by primer competition polymerase chain reaction

mdx, mdx3cv, and mdx4cv mice are among the most commonly used models for the study of Duchenne muscular dystrophy. Their disease is caused by point mutations in the dystrophin gene. Despite widespread use of these models, genotyping has not always been straightforward. Current methods require multiple polymerase chain reactions (PCRs), post-PCR manipulations, and/or special equipment/reagents. Herein we report a simple, robust PCR genotyping method based on primer competition. This approach could also be applied in genotyping other point-mutation models.

Systemic Trans-splicing adeno-associated viral delivery efficiently transduces the heart of adult mdx mouse, a model for duchenne muscular dystrophy

Trans-splicing adeno-associated viral (tsAAV) vectors hold great promise for delivering large therapeutic genes. One potential application is in the treatment of Duchenne muscular dystrophy (DMD). In this case, it is necessary to transduce whole body muscle. We demonstrated body-wide AAV-9 tsAAV transduction in normal neonatal mice. However, it was not clear whether such an approach would work in diseased mice. In this study we delivered the AAV-9 alkaline phosphatase (AP) tsAAV vector (3 x 10(12) vector genome particles per vector per mouse, tail vein injection) to 2-month-old mdx mice, the most widely used DMD model. Four months later, we observed widespread AP expression in the heart. It reached the same level as we have seen in normal neonatal puppy. Interestingly, myocardial transduction correlated with beta-myosin heavy chain expression but not with LamR, the putative AAV-9 receptor. AP expression was also detected in various skeletal muscles but at levels much lower than in normal newborn mice. Despite the existing inflammatory milieu, we did not see any appreciable increase in CD4(+) and CD8(+) T cells and macrophages in striated muscles after systemic tsAAV infection. In summary, our results have paved the way for tsAAV-mediated gene therapy for Duchenne cardiomyopathy.

Novel CLCN1 mutations and clinical features of Korean patients with myotonia congenita

Myotonia congenita (MC) is a form of nondystrophic myotonia caused by a mutation of CLCN1, which encodes human skeletal muscle chloride channel (CLC-1). We performed sequence analysis of all coding regions of CLCN1 in patients clinically diagnosed with MC, and identified 10 unrelated Korean patients harboring mutations. Detailed clinical analysis was performed in these patients to identify their clinical characteristics in relation to their genotypes. The CLCN1 mutational analyses revealed nine different point mutations. Of these, six (p.M128I, p.S189C, p.M373L, p.P480S, p.G523D, and p.M609K) were novel and could be unique among Koreans. While some features including predominant lower extremity involvement and normal to slightly elevated creatine kinase levels were consistently observed, general clinical features were highly variable in terms of age of onset, clinical severity, aggravating factors, and response to treatment. Our study is the first systematic study of MC in Korea, and shows its expanding clinical and genetic spectrums.