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Population-based estimates of survival among individuals with Duchenne muscular dystrophy (DMD) living in the United States are lacking. It is also unclear whether the association between glucocorticoid use and all-cause mortality persists in the context of other common treatments (cardiac medication, cough-assist, bilevel positive airway pressure, and scoliosis surgery) observed to delay mortality. Among 526 individuals identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network, the estimated median survival time from birth was 23.7 years. Current glucocorticoid users had a lower hazard of mortality than non-users. Individuals who ever had scoliosis surgery had a lower hazard of mortality than individuals who did not have scoliosis surgery. Individuals who ever used cough assist had a lower hazard of mortality than individuals who never used cough assist. Non-Hispanic Black individuals had a higher hazard of mortality than non-Hispanic White individuals. No differences in hazards of mortality were observed between ever versus never use of cardiac medication and ever versus never use of bilevel positive airway pressure. The glucocorticoid observation is consistent with the 2018 Care Considerations statement that glucocorticoid use continues in the non-ambulatory phase. Our observations may inform the clinical care of individuals living with DMD.

With current and anticipated disease-modifying treatments, including gene therapy, an early diagnosis for Duchenne muscular dystrophy (DMD) is crucial to assure maximum benefit. In 2009, a study from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) showed an average diagnosis age of 5 years among males with DMD born from January 1, 1982 to December 31, 2000. Initiatives were implemented by the US Centers for Disease Control and Prevention (CDC) and patient organizations to reduce time to diagnosis. We conducted a follow-up study in a surveillance cohort born after January 1, 2000 to determine whether there has been an improvement in time to diagnosis.We assessed the age of diagnosis among males with DMD born from January 1, 2000 to December 31, 2015 using data collected by six US MD STARnet surveillance sites (Colorado, Iowa, western New York State, the Piedmont region of North Carolina, South Carolina, and Utah). The analytic cohort included 221 males with definite or probable DMD diagnosis without a documented family history. We computed frequency count and percentage for categorical variables, and mean, median, and standard deviation (SD) for continuous variables.The mean [median] ages in years of diagnostic milestones were: first signs, 2.7 [2.0]; first creatine kinase (CK), 4.6 [4.6]; DNA/muscle biopsy testing, 4.9 [4.8]; and time from first signs to diagnostic confirmation, 2.2 [1.4].The time interval between first signs of DMD and diagnosis remains unchanged at 2.2 years. This results in lost opportunities for timely genetic counseling, implementation of standards of care, initiation of glucocorticoids, and participation in clinical trials.

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) phenotypes are used to describe disease progression in affected individuals. However, considerable heterogeneity has been observed across and within these two phenotypes, suggesting a spectrum of severity rather than distinct conditions. Characterizing the phenotypes and subphenotypes aids researchers in the design of clinical studies and clinicians in providing anticipatory guidance to affected individuals and their families. Using data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet), we used K-means cluster analysis to group phenotypically similar males with pediatric-onset dystrophinopathy. We identified four dystrophinopathy clusters: Classical BMD, Classical DMD, late ambulatory DMD, and severe DMD. The clusters that we identified align with both ‘classical’ and ‘non-classical’ dystrophinopathy described in the literature. Individuals with dystrophinopathies have heterogenous clinical presentations that cluster into phenotypically similar groups. Use of clinically-derived phenotyping may provide a clearer understanding of disease trajectories, reduce variability in study results, and prevent exclusion of certain cohorts from analysis. Findings from studying subphenotypes may ultimately improve our ability to predict disease progression.

Introduction: Racial/ethnic differences in diagnostic and treatment services have been identified for a range of health conditions and outcomes. The current study aimed to analyze whether there are racial/ethnic differences in the timing of diagnostic testing and treatments for males with Duchenne Muscular Dystrophy (DMD). Methods: Diagnostic and clinical data for male individuals with DMD born during 1990-2010 were analyzed from eight sites (Arizona, Colorado, Georgia, Iowa, Piedmont Region of North Carolina, western New York, South Carolina, Utah) of the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet). Seven milestones related to diagnosis/treatment experiences were selected as outcomes. Times to each milestone were estimated and compared by four racial/ethnic groups using Kaplan-Meier estimation and Cox proportional hazard models. Times between initial evaluation or diagnostic testing and later milestones were also compared by race/ethnicity. Results: We identified 682 males with definite or probable DMD of whom 61.7% were non-Hispanic White, 20.5% Hispanic, 10.6% other, and 7.2% non-Hispanic Black. Seven milestone events were studied (initial evaluation, first neurology/neuromuscular visit, diagnosis, corticosteroid treatment first offered, corticosteroid treatment started, first electrocardiogram or echocardiogram, and first pulmonary function testing). The first five milestone events occurred at an older age for non-Hispanic Black individuals compared to non-Hispanic White individuals. Time from diagnosis to first offering of corticosteroids and initiation of corticosteroid therapy was later for Hispanic individuals compared to non-Hispanic White individuals. When accounting for timing of initial evaluation/diagnosis, offering of corticosteroids continued to occur later, but first pulmonary testing occurred earlier, among Hispanic individuals compared to non-Hispanic Whites. No significant delays remained for non-Hispanic Black individuals after accounting for later initial evaluation/diagnosis. Conclusion: We described racial/ethnic differences in ages at selected diagnostic and treatment milestones. The most notable differences were significant delays for five of seven milestones in non-Hispanic Black individuals, which appeared to be attributable to later initial evaluation/diagnosis. Findings for Hispanic individuals were less consistent. Efforts to address barriers to early evaluation and diagnosis for non-Hispanic Black children with DMD may promote more timely initiation of recommended disease monitoring and interventions.

Objective: To identify factors parents considered in treatment decision making for children diagnosed with spinal muscular atrophy on newborn screening. Methods: Participants were recruited through the University of Rochester or through flyers and Cure SMA social media outreach and asked to complete a telephone or online survey. Data were analyzed through mixed methods using descriptive statistics and theme identification in narrative responses. Results: Eighteen parents with children diagnosed with spinal muscular atrophy on newborn screening participated. Thirteen of 18 chose onasemnogene abeparvovec, 2 of 18 chose risdiplam, 1 of 18 chose nusinersen, and 2 of 18 did not receive treatment. The most commonly reported factors impacting treatment choice included treatment frequency and administration method. Seventeen (94.4%) parents felt that inclusion of spinal muscular atrophy on newborn screening was positive because it could allow for better outcomes with earlier treatment. Conclusion: Treatment frequency and administration method were the most important factors for parents in determining spinal muscular atrophy treatment. Parents felt positively about newborn screening due to opportunity for earlier treatment.

In this retrospective cohort study, we characterize the health profile of preterm males with Duchenne muscular dystrophy. Major clinical milestones (ambulation cessation, assisted ventilation use, and onset of left ventricular dysfunction) and corticosteroids use in males with Duchenne muscular dystrophy identified through a population-based surveillance system were analyzed using Kaplan-Meier survival curves and Cox proportional hazards modeling. The adjusted risk of receiving any respiratory intervention among preterm males with Duchenne muscular dystrophy was 87% higher than among the corresponding full-term males with Duchenne muscular dystrophy. The adjusted risks for ambulation cessation and left ventricular dysfunction were modestly elevated among preterm compared to full-term males, but the 95% confidence intervals contained the null. No difference in the start of corticosteroid use between preterm and full-term Duchenne muscular dystrophy males was observed. Overall, the disease course seems to be similar between preterm and full-term males with Duchenne muscular dystrophy; however, pulmonary function seems to be affected earlier among preterm males with Duchenne muscular dystrophy.

INTRODUCTION/AIM Long-term efficacy and safety of dichlorphenamide (DCP) were characterized in patients with primary periodic paralysis (PPP). METHODS Patients with PPP in a double-blind, placebo-controlled study were randomly assigned to receive DCP 50 mg twice daily or placebo for 9 weeks, followed by a 52-week open-label DCP treatment phase (DCP/DCP and placebo/DCP populations). Efficacy (attack rate, severity-weighted attack rate) and safety were assessed in patients completing the study (61 weeks). In this post hoc analysis, efficacy and safety data were pooled from hyperkalemic and hypokalemic substudies. RESULTS Sixty-three adults (age, 19-76 years) completed the double-blind phase; 47 (74.6%) of these patients completed 61 weeks. There were median decreases in weekly attack and severity-weighted attack rates from baseline to week 61 (DCP/DCP [n = 25], -1.00 [P

Introduction To reduce myasthenia gravis (MG) patient risk of immunosuppressant (IS) exposure adverse events (AEs), such as infections and malignancies, and to reduce treatment burden, international guidelines recommend decreasing IS dose in stable MG patients. Methods Online surveys were conducted of self-identified MG patients and MG physician experts about the importance of IS dose reduction for MG patients who achieve prolonged periods of disease stability. Results Eighty-four percent of MG patients (n = 283) and 100% of physicians (n = 45) were concerned about long-term IS-associated AEs. Although both groups favored attempting IS reduction, they raised concerns including MG relapse, hospitalization, and uncertainty about the future. Presented with an estimated 12% significant relapse rate with IS dose reduction, 76% of patients would be willing to enroll in a randomized IS dose reduction trial. Discussion Patients and physicians favor considering IS dose reduction but are also concerned about potential negative sequelae.

Background and ObjectivesSpinal muscular atrophy (SMA) was added to the Recommended Uniform Screening Panel in July 2018 largely on the basis of the availability and efficacy of newly approved disease-modifying therapies. New York State (NYS) started universal newborn screening for SMA in October 2018. The authors report the findings from the first 3 years of screening.MethodsStatewide neonatal screening was conducted using DNA extracted from dried blood spots using a real-time quantitative PCR assay. Retrospective follow-up data were collected from 9 referral centers across the state on 34 infants.ResultsIn the first 3 years since statewide implementation, nearly 650,000 infants have been screened for SMA. Thirty-four babies screened positive and were referred to a neuromuscular specialty care center. The incidence remains lower than previously predicted. The majority (94%), including all infants with 2–3 copies of survival motor neuron (SMN) 2, have received treatment. Among treated infants, the overwhelming majority (94%; 30/32) have received gene replacement. All infants in this cohort with 3 copies of SMN2 are clinically asymptomatic posttreatment based on early clinical follow-up data. Infants with 2 copies of SMN2 are more variable in their outcomes. Electrodiagnostic outcomes data obtained from a subgroup of patients (n = 11) demonstrated either improvement or no change in compound muscle action potential (CMAP) amplitude at last clinical follow-up compared with pretreatment baseline. Most infants were treated before 6 weeks of age (median = 34.5 days of life; range 11–180 days). Delays and barriers to treatment identified by treating clinicians followed 2 broad themes: medical and nonmedical. Medical delays most commonly reported were the presence of AAV9 antibodies and elevated troponin I levels. Nonmedical barriers included delays in obtaining insurance and insurance policies regarding specific treatment modalities.DiscussionThe findings from the NYS cohort of newborn screen-identified infants are consistent with other reports of improved outcomes from early diagnosis and treatment. Additional biomarkers of motor neuron health including EMG can potentially be helpful in detecting preclinical decline.

Background and ObjectiveTo determine whether rituximab is safe and potentially beneficial, warranting further investigation in an efficacy trial for acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR-Ab+ gMG).MethodsThe B-Cell Targeted Treatment in MG (BeatMG) study was a randomized, double-blind, placebo-controlled, multicenter phase 2 trial that utilized a futility design. Individuals 21–90 years of age, with AChR-Ab+ gMG (MG Foundation of America Class II–IV) and receiving prednisone ≥15 mg/d were eligible. The primary outcome was a measure of steroid-sparing effect, defined as the proportion achieving ≥75% reduction in mean daily prednisone dose in the 4-weeks prior to week 52 and with clinical improvement or no significant worsening as compared to the 4-week period prior to randomization. The coprimary outcome was safety. Secondary outcomes included MG-specific clinical assessments. Fifty-two individuals were randomized (1:1) to a 2-cycle rituximab/placebo regimen, with follow-up through 52 weeks.ResultsOf the 52 participants included, mean ± SD age at enrollment was 55.1 ± 17.1 years; 23 (44.2%) were women and 31 (59.6%) were Myasthenia Gravis Foundation of America Class II. The mean ± SD baseline prednisone dose was 22.1 ± 9.7 mg/d. The primary steroid-sparing outcome was achieved in 60% of those on rituximab vs 56% on placebo. The study reached its futility endpoint (p = 0.03), suggesting that the predefined clinically meaningful improvement of 30% due to rituximab over placebo was unlikely to be achieved in a subsequent, larger trial. No safety issues were identified.DiscussionAlthough rituximab was safe and well-tolerated, these results suggest that there is a low probability of observing the defined clinically meaningful steroid-sparing effect over a 12-month period in a phase 3 trial of mild to moderately symptomatic AChR-Ab+ gMG.Classification of EvidenceThis study provides Class I evidence that for mild to moderate AChR-Ab+ gMG, compared with placebo, rituximab is safe but unlikely to reduce steroid use by an absolute difference of at least 30% at 1 year.Trial Registration InformationClinicalTrials.gov identifier: NCT02110706.

Introduction Clinical trials data concerning use of nusinersen in older spinal muscular atrophy (SMA) patients is lacking. We describe our center's experience in using intrathecal nusinersen for older patients in the clinical setting. Methods Retrospective study. Results Twelve patients (12-52 years old) were treated with nusinersen. Mean follow-up duration was 17.4 months (range, 4-26 months). All patients had scoliosis; 10 had spinal fusion/instrumentation. All procedures (30 cervical and 57 lumbar punctures) were technically successful. The only side effects were postprocedural headache (9%) and site pain (5.7%). Functional assessments showed stability in 6/9 patients and improvement in 3/9 patients. Subjective improvements in endurance, hand strength, and bulbar functioning critical for activities of daily living were reported in 8/12 patients. None of the patients has discontinued treatment so far. Discussion Intrathecal nusinersen can be safely delivered in older SMA patients. Available functional outcome measures are not adequate to capture meaningful subjective improvements.

Background Primary periodic paralyses are rare, hereditary skeletal muscle diseases characterized by episodic muscle weakness. Dichlorphenamide was effective and well tolerated in two studies, including one with adolescents. This analysis describes effects of dichlorphenamide among adolescents and adults. Methods Patients with primary periodic paralyses in a double-blind, controlled, crossover study were randomized to dichlorphenamide or placebo for nine weeks, with a nine-week or longer between-treatment washout period. Attack rate and severity-weighted attack rate during the final eight weeks of each treatment phase were calculated for adolescents and adults separately. Results Seven adolescents (10 to ≤17 years) and 66 adults were enrolled; five of seven adolescents were evaluable for efficacy and six for safety. Dichlorphenamide total daily dosing among adolescents was 50 mg (n = 1) or 100 mg (n = 5), and in adults was 105.7 mg (mean; n = 61). In adolescents, the median decrease from baseline in frequency of weekly attacks was greater with dichlorphenamide (−0.96) than with placebo (−0.57), similar to findings in adults (dichlorphenamide, −0.83; placebo, −0.24). Severity-weighted attack frequency was likewise reduced more with dichlorphenamide than with placebo in adolescents and adults. The most common adverse event with dichlorphenamide in adolescents was skin rash (two of six [33%]). In adults, numbness was the most common adverse event (26 of 54 [48%]); skin rash occurred less frequently (10 of 54 [19%]). Conclusions Dichlorphenamide was comparably effective and tolerated among a small number of adolescents as well as adults, although types of adverse events differed between groups.

Implementation of newborn screening for spinal muscular atrophy (SMA) in 33 US states and increased genetic carrier screening have led to an increase in early, presymptomatic diagnosis of SMA. Early treatment is critically important and is recommended for presymptomatic infants with two to four copies of survival motor neuron 2. Currently, no specific treatment recommendations exist for preterm infants with SMA. The US Food and Drug Administration does not recommend using onasemnogene abeparvovec-xioi in preterm infants. Some insurance companies interpret "preterm" to be less than 40 weeks gestational age (GA) instead of the commonly accepted 37 weeks GA, which can be a barrier to treatment access. Given the risk of rapid decline in some infants, we recommend treatment of preterm infants when they reach 37 weeks GA, based on the definitions of term GA from the World Health Organization and Centers for Disease Control and Prevention, assuming all other treatment criteria are met.

INTRODUCTION The Spinal Muscular Atrophy Health Index (SMA-HI) is a multifaceted, disease-specific, patient-reported outcome to measure an SMA patient's perception of their disease burden. In preparation for upcoming therapeutic trials, we examine the validity, reliability, and usability of the SMA-HI in adults, teenagers, and children with SMA. METHODS Using data from a cross-sectional study of 359 international adult patients with SMA, we identified the most relevant symptoms to include in the SMA-HI. We utilized factor analysis, patient interviews with adults and minors (age 8-15 years), known-group validity testing, and test-retest reliability assessments to evaluate and refine the SMA-HI. RESULTS The SMA-HI measures overall disease burden and 15 areas of SMA health. Fifteen adult patients and five patients, age 8 to 15 years, participated in semistructured qualitative interviews and found the SMA-HI to be comprehensive, easily completed, and to have clear meaning. The final SMA-HI and its subscales demonstrated good internal consistency (Cronbach α = 0.77-0.96), high test-retest reliability (intraclass correlation coefficient = 0.60-0.96), and an ability to differentiate between SMA groups with different disease severities affecting areas such as employment and ambulation (P

BackgroundEteplirsen received accelerated FDA approval for treatment of Duchenne muscular dystrophy (DMD) with mutations amenable to exon 51 skipping, based on demonstrated dystrophin production.ObjectiveTo report results from PROMOVI, a phase 3, multicenter, open-label study evaluating efficacy and safety of eteplirsen in a larger cohort.MethodsAmbulatory patients aged 7-16 years, with confirmed mutations amenable to exon 51 skipping, received eteplirsen 30 mg/kg/week intravenously for 96 weeks. An untreated cohort with DMD not amenable to exon 51 skipping was also enrolled.Results78/79 eteplirsen-treated patients completed 96 weeks of treatment. 15/30 untreated patients completed the study; this cohort was considered an inappropriate control group because of genotype-driven differences in clinical trajectory. At Week 96, eteplirsen-treated patients showed increased exon skipping (18.7-fold) and dystrophin protein (7-fold) versus baseline. Post-hoc comparisons with patients from eteplirsen phase 2 studies (4658-201/202) and mutation-matched external natural history controls confirmed previous results, suggesting clinically notable attenuation of decline on the 6-minute walk test over 96 weeks (PROMOVI: -68.9 m; phase 2 studies: -67.3 m; external controls: -133.8 m) and significant attenuation of percent predicted forced vital capacity annual decline (PROMOVI: -3.3%, phase 2 studies: -2.2%, external controls: -6.0%; p

Knowledge of health related quality of life (HRQOL) in the immediate phase following DMD diagnosis has not been well-characterized. It is important to understand HRQOL early in disease for both clinical care and studies of treatment. The relationship between parent-proxy and child self-report HRQOL and their associations with medical, psycho-social and behavioral symptoms deserve study. In this study HRQOL was measured using the PedsQL inventory in parent/caregiver and corticosteroid-naïve boys (ages 4 to 7 years) participating in the FOR-DMD study. Agreement between the parent-proxy report and the boys' self-report HRQOL was measured using intraclass correlation coefficients (ICCs). Factors associated with HRQOL, including standardized psychosocial and behavioral measures in this cross-sectional sample, were explored using correlations. The results showed that the level of agreement between 70 dyads of child self-report and parent-proxy ratings of HRQOL was poor for the generic PedsQL total score (ICC=0.48, 95% CI (0.23, 0.66)) and its subscale scores, and was similarly low for the neuromuscular disease module (ICC=0.24, 95% CI (0.00, 0.45)). Parents rated their child's HRQOL as poorer than the children rated themselves in all scales. Psychosocial outcome measures were more highly associated with HRQOL measures than disease severity or patient demographic variables. In the early phases of DMD, child and parent-proxy HRQOL ratings were discordant. In early DMD, psychosocial and behavioral aspects appear to be more relevant to HRQOL than disease severity factors.

The Charcot-Marie-Tooth Health Index (CMT-HI) is a disease-specific patient-reported outcome measure measuring overall disease burden in Charcot-Marie-Tooth (CMT) patients, designed for natural history studies and clinical trials in English-speaking affected individuals. We developed and validated its Italian Charcot-Marie-Tooth Health Index (I-CMT-HI) version. The questionnaire was translated and culturally adapted from source into Italian by two neurologists experienced in CMT and neuromuscular disorders (NMDs). The two translations were reviewed by a panel of seven experts in CMT and NMD. The provisional version was back-translated into English by a professional translator. The definitive Italian version was developed during a consensus teleconference by the panel and a patient representative from ACMT-Rete. A series of clinically and genetically characterized CMT patients completed the final questionnaire; 11 participated in a test-retest reliability assessment of the instrument. The I-CMT-HI was administered to 30 CMT patients (13 CMT1A, eight CMTX1, two CMT1B, two CMT1E, two CMT2I, one CMT2A, one CMT2N, one distal Hereditary Motor Neuropathy), with test-rest in 11:14 females and 16 males, aged (mean ± SD) 48.0 ± 16.4 years (range 18-81), with CMT Examination Score (CMTES) = 10.0 ± 4.4 (range 2-18). The I-CMT-HI mean total score was 29.4 ± 21.2 (range 0.1-60.3). The I-CMT-HI showed a high test-retest reliability: intraclass correlation coefficient = 0.95 (95% confidence interval, 0.84-0.99). No patient had difficulty in completing the questionnaire and none reported any problem with the questions' formulation. The total CMT-HI score was positively correlated with age and CMTES, with higher disease burden with increasing age and disease severity according to the CMTES. The I-CMT-HI is now ready for use in clinical studies in the Italian population.

BACKGROUND Quantifying associations between genetic mutations and loss of ambulation (LoA) among males diagnosed with childhood-onset dystrophinopathy is important for understanding variation in disease progression and may be useful in clinical trial design. METHODS Genetic and clinical data from the Muscular Dystrophy Surveillance, Tracking, and Research Network for 358 males born and diagnosed from 1982 to 2011 were analyzed. LoA was defined as the age at which independent ambulation ceased. Genetic mutations were defined by overall type (deletion/duplication/point mutation) and among deletions, those amenable to exon-skipping therapy (exons 8, 20, 44-46, 51-53) and another group. Cox proportional hazards regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS Mutation type did not predict time to LoA. Controlling for corticosteroids, Exons 8 (HR = 0.22; 95% CI = 0.08, 0.63) and 44 (HR = 0.30; 95% CI = 0.12, 0.78) were associated with delayed LoA compared to other exon deletions. CONCLUSIONS Delayed LoA in males with mutations amenable to exon-skipping therapy is consistent with previous studies. These findings suggest that clinical trials including exon 8 and 44 skippable males should consider mutation information prior to randomization.

The coronavirus disease 2019 (COVID‐19) pandemic has resulted in the reorganization of health‐care settings affecting clinical care delivery to patients with Duchenne and Becker muscular dystrophy (DBMD) as well as other inherited muscular dystrophies. The magnitude of the impact of this public health emergency on the care of patients with DBMD is unclear as they are suspected of having an increased risk for severe manifestations of COVID‐19. In this article, the authors discuss their consensus recommendations pertaining to care of these patients during the pandemic. We address issues surrounding corticosteroid and exon‐skipping treatments, cardiac medications, hydroxychloroquine use, emergency/respiratory care, rehabilitation management, and the conduct of clinical trials. We highlight the importance of collaborative treatment decisions between the patient, family, and health‐care provider, considering any geographic or institution‐specific policies and precautions for COVID‐19. We advocate for continuing multidisciplinary care for these patients using telehealth.

The coronavirus disease 2019 (COVID‐19) pandemic has resulted in reorganization of healthcare settings affecting the delivery of clinical care to patients with spinal muscular atrophy (SMA). There is a concern that patients with SMA may be at increased risk of manifesting severe symptoms of COVID‐19. Currently approved therapies for SMA improve survival and motor function; however, their delivery requires an increased exposure to the health system and a dedicated healthcare team. In this study, we discuss consensus recommendations pertaining to care of SMA patients during the pandemic. We highlight that SMA treatments should not be perceived as elective. Decisions regarding the delay of treatments should be made with consideration of the potential risks of COVID‐19 exposure and the risk of that delay. We emphasize the importance of collaborative treatment decisions between the patient, family, and healthcare provider, considering any geographic‐ or institution‐specific policies and precautions for COVID‐19.

Dystrophinopathies are caused by mutations in DMD resulting in progressive muscle weakness. They are historically divided into the more severe Duchenne (DMD) and milder Becker (BMD) muscular dystrophy phenotypes. Classification is important for research and clinical care. The purpose of this study was to describe a multi-variable approach to classifying cases from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) and to assess the accuracy of the diagnostic classification scheme. We used age at loss of mobility, molecular testing results, and age at symptom onset to classify cases as having DMD or BMD and to assess sensitivity and specificity. Mobility status showed low sensitivity and high specificity for predicting DMD (65.5% and 99.3%, respectively) and BMD (62.8% and 97.7%, respectively) phenotypes. Molecular testing showed 90.9% sensitivity and 66.4% specificity for DMD; 76.3% sensitivity and 90.0% specificity for BMD. Age of onset predicted DMD with sensitivity of 73.9% and specificity of 69.0%; BMD had 99.7% specificity and 36.7% sensitivity. Mobility status, molecular test results, and age at symptom onset are important but inconsistent measures for accurately classifying individuals into DMD or BMD phenotypes. These results have implications for prognosis in newly diagnosed individuals and for classifying phenotype in clinical trials.

ObjectiveTo identify the level of evidence for use of nusinersen to treat spinal muscular atrophy (SMA) and review clinical considerations regarding use.MethodsThe author panel systematically reviewed nusinersen clinical trials for patients with SMA and assigned level of evidence statements based on the American Academy of Neurology's 2017 therapeutic classification of evidence scheme. Safety information, regulatory decisions, and clinical context were also reviewed.ResultsFour published clinical trials were identified, 3 of which were rated above Class IV. There is Class III evidence that in infants with homozygous deletions or mutations of SMN1, nusinersen improves the probability of permanent ventilation-free survival at 24 months vs a well-defined historical cohort. There is Class I evidence that in term infants with SMA and 2 copies of SMN2, treatment with nusinersen started in individuals younger than 7 months results in a better motor milestone response and higher rates of event-free survival than sham control. There is Class I evidence that in children aged 2–12 years with SMA symptom onset after 6 months of age, nusinersen results in greater improvement in motor function at 15 months than sham control. Nusinersen was safe and well-tolerated.Clinical contextEvidence of efficacy is currently highest for treatment of infantile- and childhood-onset SMA in the early and middle symptomatic phases. While approved indications for nusinersen use in North America and Europe are broad, payer coverage for populations outside those in clinical trials remain variable. Evidence, availability, cost, and patient preferences all influence decision-making regarding nusinersen use.

The objective of this study was to investigate whether males who were born preterm took longer to receive a Duchenne muscular dystrophy diagnosis than term males. Data for males with Duchenne muscular dystrophy identified through a population-based surveillance system were analyzed using a Kaplan-Meier estimator. The first signs and symptoms were noted at a median age of 2 years in both groups. Median age when first signs and symptoms prompted medical evaluation was 2.59 years among preterm and 4.01 years among term males. Median age at definitive diagnosis was 4.25 years and 4.92 years for preterm and term males, respectively. Neither difference was statistically significant. Preterm males tended to be seen for their initial medical evaluation earlier than term males, though they were not diagnosed significantly earlier. It may take clinicians longer after the initial evaluation of preterm males to arrive at a Duchenne muscular dystrophy diagnosis.

Myasthenia gravis presents a risk factor for pregnancy and delivery, and can affect the newborn. In return, pregnancy can affect the course of myasthenia and worsen the disease during pregnancy requiring treatment modifications. Treatment optimization and drug safety should be addressed before conception. Delivery is complicated by prolonged labor. Newborns can develop neonatal myasthenia gravis, a treatable and transient disease. Patients should not be discouraged to become pregnant, but provided with supportive counseling, planning, and monitoring in a multidisciplinary team involving obstetrician, anesthesiologist, pediatrician, and neurologist. Pregnancy outcome is favorable in women who receive treatment and expert care.

Introduction As the Duchenne muscular dystrophy (DMD) population ages, it is essential that we understand the late-stage health profile and provide the appropriate care for this emerging population. Methods We undertook a descriptive study to document the health profile of a cohort of adults with DMD using data from the Muscular Dystrophy Surveillance Tracking and Research network (MD STARnet). Data included information collected from Arizona, Colorado, Iowa, Georgia, and 12 counties in western New York on individuals born since January 1982 and followed through December 2012. Results In 208 adults with DMD, the number of individuals (N) and median ages (years) at which certain critical milestones were crossed and interventions initiated were as follows: development of cardiomyopathy, N = 145 (16.7); initiation of non-invasive ventilation, N = 99 (18.0); gastrostomy, N = 47 (19.0); and death, N = 59 (21.8). Discussion These population-based data provide critical information about late-stage health profiles among adults with DMD for developing appropriate models of care. Muscle Nerve 58: 219-223, 2018.

Individuals with Duchenne muscular dystrophy (DMD) often exhibit delayed motor and cognitive development, including delayed onset of ambulation. Data on age when loss of independent ambulation occurs are well established for DMD; however, age at onset of walking has not been well described. We hypothesize that an effective medication given in early infancy would advance the age when walking is achieved so that it is closer to age-matched norms, and that this discrete event could serve as the primary outcome measure in a clinical trial. This study examined three data sets, Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet); Dutch Natural History Survey (DNHS); and Parent Project Muscular Dystrophy (PPMD). The distribution of onset of ambulation in DMD (mean ± SD) and median age, in months, at the onset of ambulation was 17.3 (±5.5) and 16.0 in MD STARnet, 21.8 (±7.1) and 20.0 in DNHS, and 16.1 (±4.4) and 15 in PPMD. Age of ambulation in these data sets were all significantly later (P < 0.001) than the corresponding age for typically developing boys, 12.1 (±1.8). A hypothetical clinical trial study design and power analyses are presented based on these data.

Myasthenia gravis (MG) is an autoimmune neuromuscular disease that causes fluctuating weakness in ocular, bulbar, and limb muscles and can, in 15% of cases, cause myasthenic crisis, a neurologic emergency characterized by respiratory failure. Although infrequent, MG needs to be promptly recognized and treated because the potential for improvement and remission is very high. The diagnosis of MG can be challenging and delayed because of the fluctuating nature of muscle weakness and the overlap of signs and symptoms with other neuromuscular diseases.This article reviews the importance of prompt recognition of the typical signs and symptoms, best tests to confirm the diagnosis, currently available acute and chronic treatment modalities, the role of thymectomy, and the natural history of the disease. Special consideration related to the diagnosis and management in women during pregnancy and in children will also be reviewed. This article also includes an overview of congenital myasthenic syndromes.Recent significant efforts in standardizing and improving the care of patients with MG have occurred, as well as new momentum in developing new drugs for patients with MG who do not adequately respond to currently available treatments. The number of clinical trials and drugs in development for MG is steadily increasing. Eculizumab has been recently approved by the US Food and Drug Administration (FDA) for adult patients with generalized MG who are acetylcholine receptor-antibody positive, based on the REGAIN (Safety and Efficacy of Eculizumab in Refractory Generalized Myasthenia Gravis) study, a phase 3, randomized, double-blind, placebo-controlled, multicenter trial. An international, multicenter, randomized trial comparing thymectomy plus prednisone with prednisone alone has demonstrated that thymectomy improves clinical outcome in patients with nonthymomatous MG. Clinical care guidelines have been published, and the recommendations for clinical research standards and the Myasthenia Gravis Foundation of America MGFA clinical classification published in 2000 have become widely accepted by the clinical and research community of MG experts.MG is a highly treatable disease with many effective treatment modalities available and with a natural history that continues to improve thanks to better diagnostic tests and effective drugs. The diagnosis and management of patients affected by MG can be highly rewarding for any neurologist as most patients are able to live normal lives if treated appropriately. Nevertheless, future research is needed to address unresolved clinical issues, such as when and how to discontinue immunosuppressive medications in patients in remission, the role and timing of thymectomy in children, and better treatment options for refractory patients.

Summary Background The Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone (MGTX) showed that thymectomy combined with prednisone was superior to prednisone alone in improving clinical status as measured by the Quantitative Myasthenia Gravis (QMG) score in patients with generalised non-thymomatous myasthenia gravis at 3 years. We investigated the long-term effects of thymectomy up to 5 years on clinical status, medication requirements, and adverse events. Methods We did a rater-blinded 2-year extension study at 36 centres in 15 countries for all patients who completed the randomised controlled MGTX and were willing to participate. MGTX patients were aged 18 to 65 years at enrolment, had generalised non-thymomatous myasthenia gravis of less than 5 years' duration, had acetylcholine receptor antibody titres of 1·00 nmol/L or higher (or concentrations of 0·50–0·99 nmol/L if diagnosis was confirmed by positive edrophonium or abnormal repetitive nerve stimulation, or abnormal single fibre electromyography), had Myasthenia Gravis Foundation of America Clinical Classification Class II–IV disease, and were on optimal anticholinesterase therapy with or without oral corticosteroids. In MGTX, patients were randomly assigned (1:1) to either thymectomy plus prednisone or prednisone alone. All patients in both groups received oral prednisone at doses titrated up to 100 mg on alternate days until they achieved minimal manifestation status. The primary endpoints of the extension phase were the time-weighted means of the QMG score and alternate-day prednisone dose from month 0 to month 60. Analyses were by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00294658. It is closed to new participants, with follow-up completed. Findings Of the 111 patients who completed the 3-year MGTX, 68 (61%) entered the extension study between Sept 1, 2009, and Aug 26, 2015 (33 in the prednisone alone group and 35 in the prednisone plus thymectomy group). 50 (74%) patients completed the 60-month assessment, 24 in the prednisone alone group and 26 in the prednisone plus thymectomy group. At 5 years, patients in the thymectomy plus prednisone group had significantly lower time-weighted mean QMG scores (5·47 [SD 3·87] vs 9·34 [5·08]; p=0·0007) and mean alternate-day prednisone doses (24 mg [SD 21] vs 48 mg [29]; p=0·0002) than did those in the prednisone alone group. 14 (42%) of 33 patients in the prednisone group, and 12 (34%) of 35 in the thymectomy plus prednisone group, had at least one adverse event by month 60. No treatment-related deaths were reported during the extension phase. Interpretation At 5 years, thymectomy plus prednisone continues to confer benefits in patients with generalised non-thymomatous myasthenia gravis compared with prednisone alone. Although caution is appropriate when generalising our findings because of the small sample size of our study, they nevertheless provide further support for the benefits of thymectomy in patients with generalised non-thymomatous myasthenia gravis. Funding National Institutes of Health, National Institute of Neurological Disorders and Stroke.

ObjectiveTo report our experience delivering intrathecal nusinersen through cervical puncture in patients with spinal muscular atrophy (SMA) with no lumbar access.BackgroundSMA is a neuromuscular disorder characterized by profound muscle weakness, atrophy, and paralysis due to degeneration of the anterior horn cells. Nusinersen, the first Food and Drug Administration–approved treatment for SMA, is administered intrathecally via lumbar puncture; however, many patients with SMA have scoliosis or solid spinal fusion with hardware that makes lumbar access impossible. Studies in primates have demonstrated better spinal cord tissue concentration with intrathecal injections than with intracerebral ventricular injections. Therefore we have used C1/C2 puncture as an alternative to administer nusinersen.MethodRetrospective chart review.ResultsIntrathecal nusinersen via cervical puncture was given to 3 patients who had thoracic and lumbosacral spinal fusion: a 12-year-old girl with type 1 SMA and 2 17-year-old girls with type 2 SMA. Cervical puncture was performed without deep sedation under fluoroscopic guidance using a 25-G or a 24-G Whitacre needle in the posterior aspect of C1-C2 interspace and full dose of nusinersen (12 mg/5 mL) was injected after visualizing free CSF flow. Patients completed their 4 loading doses and first maintenance dose of nusinersen, and 15 procedures were successful and well-tolerated.ConclusionCervical puncture is a feasible alternative delivery route to administer intrathecal nusinersen in patients with longstanding SMA and spine anatomy precluding lumbar access when done by providers with expertise in this procedure.

Spinal muscular atrophy (SMA) is a monogenic anterior horn disease caused by mutations in the SMN1 gene leading to lack of SMN protein necessary for motor neuron functioning and survival. Phenotypic severity is modulated primarily by the amount of SMN protein produced by the paralogue SMN2 gene that differs from SMN1 by a critical single-nucleotide polymorphism in exon 7 (C to T) resulting in only 10%–15% of full-length functioning SMN protein. The phenotypes include subgroups with different age at onset, severity, and rate of progression: babies with type 1 SMA have onset of weakness before 6 months, are never able to sit, and have 8% survival at 20 months; babies with type 2 have symptoms onset after 6 months, they reach the ability to sit but never walk; children and teenagers with type 3 are able to walk, become progressively weaker, and eventually lose the ability to walk; the ultra-rare type 4 with adult onset has a very slow progression of lower extremity weakness. Nusinersen is an antisense oligonucleotide that corrects pre-mRNA splicing to promote inclusion of exon 7 in the SMN2 mRNA transcript, resulting in increased production of full-length functioning SMN protein.

Introduction Anecdotal reports from families and care providers suggest a wide variation in services received by individuals with Duchenne/Becker muscular dystrophy (DBMD). Methods We documented the type and frequency of health services received by individuals with DBMD using the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet) interview data released in June 2012. Interviews with eligible caregivers from 5 sites (Arizona, Colorado, Georgia, Iowa, and western New York) were conducted from April 2007 to March 2012. Results Two hundred ninety-six caregivers (66% of those contactable) participated in the interview. There were significant differences among sites in the specialists seen and services received. Concurrence with cardiac recommendations was higher than that with respiratory recommendations. Conclusions The results of this survey support and quantify the anecdotal reports from families and care providers regarding the disparities in services received by individuals with DBMD. It remains to be determined whether these differences affect outcomes.

Background The rate of symptom progression during pregnancy in myotonic dystrophy (DM) is not currently known. Further, there is little data regarding the rate of pregnancy complications and neonatal outcomes in DM. Objective This study assesses symptom progression and complication rates during pregnancy in women with DM. Methods DM women completed surveys regarding their prior pregnancies. Participants identified complications during their pregnancies and completed the Myotonic Dystrophy Health Index-Short Form (MDHI-SF) to measure their disease burden and identify the severity of select symptoms six-months prior to, during, and six-months after their first pregnancy. Results 152 women with DM reported on 375 pregnancies. Among these pregnancies, there was a 32.5% miscarriage rate. Some complications were common including: pre-term labor (27.8%), pre-eclampsia (10.4%), and peripartum hemorrhage (13.9%). Participants' perception of their mobility and ability to perform activities, as measured by the MDHI-SF, worsened during pregnancy and did not recover during the post-partum period. Discussion Miscarriage, maternal disease progression during pregnancy, and other pregnancy related complications may occur in DM. Women with DM should be counseled on these potential risks prior to considering pregnancy.

Duchenne and Becker muscular dystrophy are X-linked neuromuscular disorders characterized by progressive muscle degeneration. Despite the involvement of multiple systems, secondary conditions among affected males have not been comprehensively described. Two hundred nine caregivers of affected males (aged 3-31 years) identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network completed a mailed survey that included questions about secondary conditions impacting multiple body functions. The 5 most commonly reported conditions in males with Duchenne were cognitive deficits (38.4%), constipation (31.7%), anxiety (29.3%), depression (27.4%), and obesity (19.5%). Higher frequencies of anxiety, depression, and kidney stones were found among nonambulatory males compared to ambulatory males. Attention-deficit hyperactivity disorder (ADHD) was more common in ambulatory than nonambulatory males. These data support clinical care recommendations for monitoring of patients with Duchenne or Becker muscular dystrophy by a multidisciplinary team to prevent and treat conditions that may be secondary to the diagnosis.

Congenital neuromuscular disorders, such as Duchenne muscular dystrophy (DMD), spinal muscular atrophy (SMA), and Pompe disease (acid maltase deficiency [AMD]), are candidates for universal newborn screening (NBS). In this article, we discuss the future path of NBS for these disorders with particular emphasis on DMD NBS, because of the likely approval of new gene-modifying treatments, the possible benefits of earlier treatment with corticosteroids, and the recently demonstrated feasibility of a 2-tiered approach to NBS with screening by creatine kinase (CK) levels in dried blood spots followed by mutation detection in those with elevated CK. The cystic fibrosis (CF) NBS program is a successful model for NBS. CF outcomes have consistently improved into adulthood following introduction of CF NBS because considerable resources have been devoted to practices that include: attention to improving laboratory screening, consistent confirmatory testing and immediate referral of all newly diagnosed infants to designated CF care centers that follow established practice guidelines, and ongoing evaluation of CF care centers via a centralized clinical database. Like CF, DMD, SMA, and infantile AMD are inexorably debilitating and require lifetime multidisciplinary clinical management. NBS would address the delays in diagnosis that prevent patients from receiving timely treatments. Standardized care following early diagnosis would reduce disparities in clinical care and outcomes. NBS in these neuromuscular disorders should be implemented, utilizing lessons learned from the past 20 years of CF NBS: standardized protocols for all patients identified by DMD NBS, longitudinal follow-up in multidisciplinary clinics, and coordinated oversight of these clinics.

Introduction Nondystrophic myotonias (NDM) are muscle channelopathies characterized by clinical and electrical myotonia. Little is known about pregnancy in NDM. The aim of this work was to assess pregnancy outcomes in women with NDM. Methods In this investigation, we utilized a cross-sectional approach and obtained questionnaire data and medical record review information. Pregnancy outcomes were compared with U.S. national data. Results Twenty-five women completed the study. There were 63 pregnancies with 53 live births, 8 miscarriages, 4 terminations, and 1 stillbirth. The infertility rate was 28% (above the U.S. average). Fetal distress was reported in 11.7% (U.S. average 3.6%) of the patients. NDM symptoms worsened in 62% of pregnancies. In those who worsened, symptoms usually resolved completely (66%) or partially (32%) after delivery in 2 days to 12 months, the majority (76%) within 3 months. Conclusions Most pregnancy outcomes were favorable. NDM worsened in nearly two-thirds of pregnancies, but usually improved shortly after delivery. Incidences of infertility and fetal distress were higher than overall U.S. rates. Muscle Nerve 52: 1013–1015, 2015

Objective: To review current approaches for obtaining patient data in Duchenne muscular dystrophy (DMD) and consider how monitoring and comparing outcome measures across DMD clinics could facilitate standardized and improved patient care. Methods: We reviewed annual standardized data from cystic fibrosis (CF) clinics and DMD care guidelines and consensus statements; compared current approaches to obtain DMD patient data and outcome measures; and considered the best method for implementing public reporting of outcomes, to drive improvements in health care delivery. Results: Current methods to monitor DMD patient information (MD STARnet, DuchenneConnect, and TREAT-NMD) do not yet provide patients with comparative outcome data. The CF patient registry allows for reporting of standard outcomes across clinics and is associated with improved CF outcomes. A similar patient registry is under development for the Muscular Dystrophy Association (MDA) clinic network. Suggested metrics for quality care include molecular diagnosis, ambulatory status and age at loss of ambulation, age requiring ventilator support, and survival. Conclusions: CF longevity has increased by almost 33% from 1986 to 2010, in part due to a CF patient registry that has been stratified by individual care centers since 1999, and publically available since 2006. Implementation of outcome reporting for MDA clinics might promote a similar benefit to patients with DMD.

The use of corticosteroids for treatment of Duchenne and Becker muscular dystrophy in clinical practice from 1991 through 2005 was reviewed in a large population-based cohort (MD STARnet) of boys in 4 regional sites and 6 clinics of the United States. Corticosteroid use increased from 20% (11 of 56 individuals) in 1991 to 44% (93 of 218 individuals) in 2005. Average use varied by site and ranged from 15% to 49%. The median age of corticosteroid initiation was 6.9 years (range, 3.7-17.4 years). Dosage and growth information was available for 102 participants and showed a median dose as 0.729 mg/kg for prednisone and 0.831 mg/kg for deflazacort. T. The most common reasons that corticosteroids were discontinued included weight gain, behavioral side effects, and loss of ambulation, resulting in full-time wheelchair use. Substantial variations in clinical practice were identified among study sites.

The type and frequency of diagnostic testing was analyzed in a population-based cohort of boys with Duchenne muscular dystrophy or Becker muscular dystrophy. Use of muscle biopsy declined from 66.0% of boys born between January 1982 and September 1987 to 32.6% born between April 1999 and September 2004. DMD mutation was documented for 345 (73.4%) boys. Deletions were more common and point mutations were less common than that has been reported in specialty clinic or laboratory-based cohorts. Deletion of one or more exons was detected in 270 individuals (57.4% of all patients and 78.3% with a DMD mutation). Duplication was identified in 39 individuals (8.3% of all patients and 11.3% with a DMD mutation). Point mutation, small insertion, or small deletion was found in 36 individuals (7.7% of all patients and 10.4% with a DMD mutation). Point mutation analysis was performed in only 37 of 130 (28.5%) individuals with negative deletion and/or duplication testing.

Background: Patients with myotonic dystrophy type 1 (DM1) frequently have symptoms of excessive daytime sleepiness (EDS). Some patients with DM1 show sleep-onset REM, similar to that observed in narcolepsy. Narcolepsy is characterized by impaired hypocretin (Hcrt) neurotransmission. Objective: To test for dysregulation of Hcrt neurotransmission in a prospective cohort of patients with DM1. Methods: Hcrt levels in CSF were measured by radioimmunoassay. Sleep physiology was assessed by overnight polysomnography (PSG) and a multiple sleep latency test (MSLT). Splicing of Hcrt receptor 1 and 2 (HcrtR1 and HcrtR2) mRNA was examined in postmortem samples of temporal cortex. Results: Seventeen of 38 patients with DM1 reported symptoms of EDS. Among patients with DM1 with EDS who underwent PSG/MSLT, 7 of 13 showed reduced sleep latency, sleep-onset REM, or both. However, CSF Hcrt levels in DM1 (mean 277 pg/mL, n = 38) were not different from controls (mean 277 pg/mL, n = 33). Also, splicing of HcrtR1 and HcrtR2 mRNA in patients with DM1 was similar to controls. Conclusions: Excessive daytime sleepiness and dysregulation of REM sleep occur frequently in patients with myotonic dystrophy type 1 (DM1). However, the pathophysiologic basis is distinct from narcolepsy, as patients with DM1 do not have a consistent defect of Hcrt release or receptor splicing.

To characterize and compare electrical myotonia in myotonic dystrophy type 1 (DM1) and type 2 (DM2), 16 patients with genetically confirmed DM1 and 17 patients with DM2 underwent standardized concentric needle electromyography of deltoid, biceps, extensor digitorum communis, first dorsal interosseous, tensor fascia lata (TFL), vastus lateralis (VL), tibialis anterior, and thoracic paraspinal muscles. Eight needle insertions per muscle were made by electromyographers blinded to DM type who recorded the presence and type of myotonia (e.g., classic waxing-waning or less specific waning discharges). Manual muscle testing was performed by a physical therapist. Overall, myotonia was more elicitable in DM1 than DM2; only in VL and TFL was myotonia more elicitable in DM2 than DM1. The major type of myotonia was waxing-waning in DM1, and waning in DM2. Four DM2 (24%), but no DM1 patients had only waning myotonia. In the arms, myotonia was distally predominant in both DM1 and DM2. In the legs, it was distally predominant in DM1, but both proximal and distal in DM2. The severity of myotonia was positively correlated with muscle weakness and with the presence of waxing and waning discharges in DM1, but with neither in DM2. Thus, myotonia is qualitatively and quantitatively different in DM1 than DM2. Except for proximal leg muscles, myotonia is more evocable in DM1 than DM2. It tends to be waxing-waning in DM1 but waning in DM2, thus making electrodiagnosis of DM2 more challenging. Its severity correlates with muscle weakness and the presence of waxing-waning discharges in DM1 but not DM2.

Objective: To determine the short-term and long-term effects of dichlorphenamide (DCP) on attack frequency and quality of life in hyperkalemic (HYP) and hypokalemic (HOP) periodic paralysis. Methods: Two multicenter randomized, double-blind, placebo-controlled trials lasted 9 weeks (Class I evidence), followed by a 1-year extension phase in which all participants received DCP. Forty-four HOP and 21 HYP participants participated. The primary outcome variable was the average number of attacks per week over the final 8 weeks of the double-blind phase. Results: The median attack rate was lower in HOP participants on DCP than in participants on placebo (0.3 vs 2.4, p = 0.02). The 9-week mean change in the Physical Component Summary score of the Short Form–36 was also better in HOP participants receiving DCP (treatment effect = 7.29 points, 95% confidence interval 2.26 to 12.32, p = 0.006). The median attack rate was also lower in HYP participants on DCP (0.9 vs 4.8) than in participants on placebo, but the difference in median attack rate was not significant ( p = 0.10). There were no significant effects of DCP on muscle strength or muscle mass in either trial. The most common adverse events in both trials were paresthesia (47% DCP vs 14% placebo, both trials combined) and confusion (19% DCP vs 7% placebo, both trials combined). Conclusions: DCP is effective in reducing the attack frequency, is safe, and improves quality of life in HOP periodic paralysis. Classification of evidence: These studies provide Class I evidence that DCP significantly reduces attack frequency in HOP but lacked the precision to support either efficacy or lack of efficacy of DCP in HYP.

Background: Distal myopathy with rimmed vacuoles (DMRV) is an autosomal-recessive disorder with preferential involvement of the tibialis anterior muscle that starts in young adulthood and spares quadriceps muscles. The disease locus has been mapped to chromosome 9p1-q1, the same region as the hereditary inclusion body myopathy (HIBM) locus. HIBM was originally described as rimmed vacuole myopathy sparing the quadriceps; therefore, the two diseases have been suspected to be allelic. Recently, HIBM was shown to be associated with the mutations in the gene encoding the bifunctional enzyme, UDP- N -acetylglucosamine 2-epimerase/ N -acetylmannosamine kinase ( GNE ). Objective: To determine whether DMRV and HIBM are allelic. Methods: The GNE gene was sequenced in 34 patients with DMRV. The epimerase activity in lymphocytes from eight DMRV patients was also measured. Results: The authors identified 27 unrelated DMRV patients with homozygous or compound-heterozygous mutations in the GNE gene. DMRV patients had markedly decreased epimerase activity. Conclusions: DMRV is allelic to HIBM. Various mutations are associated with DMRV in Japan. The loss-of-function mutations in the GNE gene appear to cause DMRV/HIBM.

Myasthenia gravis (MG) is the most common autoimmune disease affecting neuromuscular junction transmission. MG is characterized by muscle weakness that worsens with activity and fluctuates over the course of the day. Involvement of respiratory musculature can lead to life-threatening crisis requiring intensive care unit care. Antibody testing is positive in most patients with MG. Treatment of MG includes short-term symptomatic treatment, chronic immunosuppression, surgical intervention, and immunomodulatory therapies for severe disease or crisis. We review advances in 5 areas relevant to diagnosis and management of MG: the role of IV immunoglobulin vs plasmapharesis in myasthenic crisis and severe disease; the clinical characterization of patients with antibodies to muscle-specific tyrosine kinase receptors; old and new investigational treatments; management of MG in pregnancy; and new confirmatory diagnostic tests.

Fat embolization is common after long bone fractures. Presentations range from asymptomatic to the potentially fatal fat embolism syndrome (FES), a clinical triad of respiratory distress, neurologic changes, and a petechial rash.1 FES is not a well-recognized complication in Duchenne muscular dystrophy (DMD). We report 8 patients with DMD with FES after low-energy trauma, and discuss presenting features unique to this patient population.