Failure of early diagnosis in symptomatic Duchenne muscular dystrophy

How do fine and gross motor skills develop in preschool boys with Duchenne Muscular Dystrophy?

BACKGROUND

Boys with Duchenne Muscular Dystrophy (DMD) experience both fine and gross motor problems. Nowadays, early intervention focuses almost exclusively on gross motor skills.

AIMS

We aimed to explore early motor development in preschool boys with DMD and investigate the influence of cognition.

METHODS AND PROCEDURES

Seventeen boys with DMD (11 months- 6 years) were compared to typically developing (TD) peers and followed-up with the Bayley Scales of Infant and Toddler Development (Bayley-III); Peabody developmental motor scales (PDMS-II) and Motor Function Measure (MFM-20). The longitudinal evolution of fine and gross motor skills was investigated using linear mixed effect models (LMM). Cognition was added to the LMM as a covariate.

OUTCOMES AND RESULTS

Preschool boys with DMD scored lower compared to TD peers on both fine and gross motor skills (p<0.001). The evolution of motor development was subscale-dependent. A significant influence of cognition was found on different subscales (p= 0.002-0.04).

CONCLUSIONS AND IMPLICATIONS

Preschool boys with DMD do not achieve the same functioning level as TD boys. Cognition plays a crucial role in the evolution of motor skills. Our results suggest a shift to a broader psychomotor approach including both fine and gross motor skills, also considering the impact of cognition. WHAT THIS PAPER ADDS?: Our study provides a detailed mapping of early fine and gross motor development in preschool boys with Duchenne Muscular Dystrophy (DMD) and describes the influence of cognition on both fine and gross motor skills. Preschool boys with DMD do not achieve the same functioning level compared to typically developing boys. They score significantly lower on both fine and gross motor skills. The evolution of fine and gross motor development was subscale-dependent e.g. a negative-positive evolution was seen for grasping skills, with a tipping point around the age of four; stationary scaled scores decreased followed by a stabilization around the age four to five and locomotion scaled scores remained stable over time. Finally, we also found that cognition plays a crucial role in the evolution of both fine and gross motor skills. These new insights in the evolution of early motor development could be of added value for future clinical trials in young boys with DMD. Subsequently, increased alertness to early symptoms, e.g. developmental delay, may advance the age of diagnosis, as well as associated early intervention.

Early motor, cognitive, language, behavioural and social emotional development in infants and young boys with Duchenne Muscular Dystrophy- A systematic review

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disorder caused by mutations in the dystrophin gene. Deficiency of the dystrophin protein causes not only motor, but also cognitive, language, behavioural and social emotional problems. This is the first systematic review investigating five early developmental domains in boys with DMD between 0 and 6 years old. Interactions between different domains and links with mutation types and sites were explored. A systematic search was performed in PubMed, Web of Science and Scopus. An adapted version of the Scottish Intercollegiate Guidelines Network (SIGN) Checklists for case-control and cohort studies was used to evaluate quality. Fifty-five studies of high or acceptable quality were included. One was an RCT of level 1b; 50 were cohort studies of level 2b; and four were an aggregation of case-control and cohort studies receiving levels 2b and 3b. We found that young boys with DMD experienced problems in all five developmental domains, with significant interactions between these. Several studies also showed relationships between mutation sites and outcomes. We conclude that DMD is not only characterised by motor problems but by a more global developmental delay with a large variability between boys. Our results emphasise the need for harmonisation in evaluation and follow-up of young boys with DMD. More high-quality research is needed on the different early developmental domains in young DMD to facilitate early detection of difficulties and identification of associated early intervention strategies.

"If you cannot measure it, you cannot improve it". Outcome measures in Duchenne Muscular Dystrophy: current and future perspectives

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive neuromuscular disorder primarily affecting males, caused by mutations in the dystrophin gene. The absence of dystrophin protein leads to progressive skeletal muscle degeneration. Recent advances in the therapeutic landscape underscore the need to identify appropriate outcome measures to assess treatment efficacy in ambulant and non-ambulant DMD patients, across clinical and research settings. This is essential for accurately evaluating new treatments and attributing therapeutic benefits.It is crucial to establish a robust correlation between outcome scores and disease progression patterns. This task is challenging since functional test performance may be influenced by different patient's characteristics, including the physiological evolution of the neurodevelopment together with the disease progression. While widely used DMD outcomes such as the North Star Ambulatory Assessment, the 6-Minute Walking Test, the 4 stairs climbed, and the Performance of the Upper Limb exhibit reliability and validity, their clinical significance is influenced by the wide phenotype and progression variability of the disease.We present and discuss the features (relevance, quantifiability, validity, objectivity, reliability, sensitivity, specificity, precision) of available DMD outcome measures, including new potential measures that may be provided by digital tools and artificial intelligence.

Caregiver Burden with Duchenne and Becker Muscular Dystrophy in Japan: A Clinical Observation Study

Objective Skeletal muscle weakness and cardiomyopathy can be seen in carriers of dystrophinopathy. Therefore, the health management of caregivers of Duchenne/Becker muscular dystrophy (DMD/BMD) patients who are themselves carriers is an important issue. However, few studies have focused on caregivers who have dystrophin mutations. Methods In this cross-sectional study conducted at five hospitals, the daily living, situation medical treatment status, genetic testing, physical assessment, care burden, and quality of life of caregivers of DMD/BMD patients were surveyed. Results The subjects were 36 main caregivers (mean age 55.7±8.4 years old), of whom 52.8% were diagnosed as carriers, 8.3% were noncarriers, and 38.9% were not confirmed. In addition, half of the caregivers were not examined regularly at medical institutions. Of all caregivers, 54.3% had muscle or cardiac symptoms, and 75% had elevated serum creatine kinase levels. The mean Zarit Caregiver Burden Interview (ZBI) total score of current caregivers was 20.9±13.1. The frequency of a ZBI total score ≥25 was significantly higher in caregivers diagnosed as carriers than in caregivers unexamined as carriers (p=0.04). The health-related quality of life score (Short Form 36; SF-36) in caregivers was slightly lower than the Japanese standard scores in the sections of physical functioning, role limitations-physical, bodily pain, and social functioning. Conclusion Some caregivers of DMD/BMD patients can themselves have muscular or cardiac symptoms and a heavy care burden. It is therefore necessary for carrier caregivers, especially women, to undergo regular health checkups and receive appropriate health management.

Coexistence of a Heterozygous Caveolin-3 Deletion and a Novel Dystrophin Gene Mutation in a Duchenne Muscular Dystrophy Patient

Inherited muscular abnormalities are debilitating disorders that greatly diminish the quality of life in affected individuals. Mutations in proteins such as dystrophin and caveolin, which together with other proteins form structural connections between the cytoskeleton and the extracellular matrix, are frequently the culprit of muscular dystrophies. In this case report, we describe a patient with a novel pathogenic dystrophin mutation co-existing with a caveolin-3 deletion. While genetically composed of this unique combination, the patient phenotypically presented with a primary clinical manifestation of Duchenne muscular dystrophy (DMD) in contrast to other cases of dual mutations in dystrophin and dystrophin-associated proteins.

Time to diagnosis of Duchenne muscular dystrophy in Austria and Germany

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder manifesting in early childhood with progressive muscular weakness and atrophy, and resulting in early loss of ambulation. The collection and evaluation of epidemiological data for this disease is crucial for an early diagnosis and disease management. In Germany, data are collected via the TREAT-NMD DMD patient registry ( www.dmd-register.de ). In contrast, data collection in Austria has not yet been performed systematically. For collecting data from Austrian DMD patients, an online survey of the patient's caregivers was conducted. Data of 57 patients were collected entailing initial symptoms, diagnosis and therapeutic measures. Comparable data has been collected for Germany via the TREAT-NMD DMD patient registry. 57 DMD patients aged 4-34 years completed the Austrian survey. On average, first symptoms of the disease appeared at the age of 3.1 years. As the most frequent first symptom, 46% of the patients described problems in climbing stairs. In 40% of the patients, DMD was diagnosed early due to an accidentally detected hyperCKemia in infancy or early childhood. Corticosteroids represented the main therapeutic option in our cohort. At the time of the survey, only 52% of the patients were treated with corticosteroids. Patients from Germany reported that first symptoms appeared at the age of 3.06 years. Diagnosis was established by genetic testing or muscle biopsy. 47% of the patients were treated with corticosteroids. Time between first symptoms and diagnosis was 7 months in Austria, and 4.7 months in Germany, respectively. Compared to earlier international studies, the Austrian data show encouraging results regarding earlier start of corticosteroid therapy in a larger percentage of patients. Austrian and German data show a trend towards an earlier diagnosis of DMD, while the age at symptom onset was similar to previous studies. The collection and evaluation of epidemiological data of DMD patients is important and will hopefully contribute to accelerate DMD diagnosis and treatment access for the patients.

Language Development in Preschool Duchenne Muscular Dystrophy Boys

BACKGROUND

the present study aims to assess language in preschool-aged Duchenne muscular dystrophy (DMD) boys with normal cognitive quotients, and to establish whether language difficulties are related to attentional aspects or to the involvement of brain dystrophin isoforms.

METHODS

20 children aged between 48 and 72 months were assessed with language and attention assessments for preschool children. Nine had a mutation upstream of exon 44, five between 44 and 51, four between 51 and 63, and two after exon 63. A control group comprising 20 age-matched boys with a speech language disorder and normal IQ were also used.

RESULTS

lexical and syntactic comprehension and denomination were normal in 90% of the boys with Duchenne, while the articulation and repetition of long words, and sentence repetition frequently showed abnormal results (80%). Abnormal results were also found in tests assessing selective and sustained auditory attention. Language difficulties were less frequent in patients with mutations not involving isoforms Dp140 and Dp71. The profile in Duchenne boys was different form the one observed in SLI with no cognitive impairment.

CONCLUSION

The results of our observational cross-sectional study suggest that early language abilities are frequently abnormal in preschool Duchenne boys and should be assessed regardless of their global neurodevelopmental quotient.

Time to diagnosis of Duchenne muscular dystrophy remains unchanged: Findings from the Muscular Dystrophy Surveillance, Tracking, and Research Network, 2000-2015

INTRODUCTION/AIMS

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.

METHODS

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.

RESULTS

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].

DISCUSSION

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.

A population-based study of mortality due to muscular dystrophies across a 36-year period in Spain

Muscular dystrophies (MD) are a group of rare hereditary degenerative diseases. Our aim was to analyze the mortality pattern in Spain from 1981 to 2016 to assess the temporal trend and discern possible geographic differences using population-based data. Annual deaths related to MD were obtained from the National Statistics Institute with codes 359.1 of the ICD-9 (1981–1998) and G71.0 of the ICD-10 (1999–2016). Age-adjusted mortality rates were calculated and changes in mortality trends were identified. The standardized mortality ratios (SMR) and their respective 95% confidence intervals were calculated by district for 1999–2016. Smoothed SMRs and posterior probability were also assessed and then mapped to look for patterns or geographic distribution. All rates were expressed per 1,000,000 inhabitants. A total of 2,512 deaths (73.8% men) were identified. The age-adjusted mortality rates varied from 0.63 (95% CI 0.40–0.95) in 1981 to 1.51 (95% CI 1.17–1.93) in 2016. MD mortality showed a significant increase of 8.81% per year (95% CI 5.0–12.7) from 1981 to 1990, remaining stable afterwards. Areas with risk of death higher than expected for Spain as a whole were identified, not showing a specific regional pattern. In conclusion, the rising trend in MD mortality might be attributable to advanced improvements in diagnostic techniques leading to a rise in prevalence. Further research on the districts with the highest mortality would be necessary.

Clinical and Genetic Characteristics in Young, Glucocorticoid-Naive Boys With Duchenne Muscular Dystrophy

BACKGROUND AND OBJECTIVES

Duchenne muscular dystrophy (DMD) is a pediatric neuromuscular disorder caused by mutations in the dystrophin gene. Genotype-phenotype associations have been examined in glucocorticoid-treated boys, but there are few data on the young glucocorticoid-naive DMD population. A sample of young glucocorticoid-naive DMD boys is described, and genotype-phenotype associations are investigated.

METHODS

Screening and baseline data were collected for all the participants in the Finding the Optimum Corticosteroid Regime for Duchenne Muscular Dystrophy (FOR-DMD) study, an international, multicenter, randomized, double-blind, clinical trial comparing 3 glucocorticoid regimens in glucocorticoid-naive, genetically confirmed boys with DMD between 4 and <8 years of age.

RESULTS

One hundred ninety-six boys were recruited. The mean ± SD age at randomization was 5.8 ± 1.0 years. The predominant mutation type was out-of-frame deletions (67.4%, 130 of 193), of which 68.5% (89 of 130) were amenable to exon skipping. The most frequent mutations were deletions amenable to exon 51 skipping (13.0%, 25 of 193). Stop codon mutations accounted for 10.4% (20 of 193). The mean age at first parental concerns was 29.8 ± 18.7 months; the mean age at genetic diagnosis was 53.9 ± 21.9 months; and the mean diagnostic delay was 25.9 ± 18.2 months. The mean diagnostic delay for boys diagnosed after an incidental finding of isolated hyperCKemia (n = 19) was 6.4 ± 7.4 months. The mean ages at independent walking and talking in sentences were 17.1 ± 4.2 and 29.0 ± 10.7 months, respectively. Median height percentiles were below the 25th percentile regardless of age group. No genotype-phenotype associations were identified expect for boys with exon 8 skippable deletions, who had better performance on time to walk/run 10 m (p = 0.02) compared to boys with deletions not amenable to skipping.

DISCUSSION

This study describes clinical and genetic characteristics of a sample of young glucocorticoid-naive boys with DMD. A low threshold for creatine kinase testing can lead to an earlier diagnosis. Motor and speech delays were common presenting symptoms. The effects of low pretreatment height on growth and adult height require further study. These findings may promote earlier recognition of DMD and inform study design for future clinical trials. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT01603407.

Lessons Learned From Translational Research in Neuromuscular Diseases: Impact on Study Design, Outcome Measures and Managing Expectation

Spinal Muscular Atrophy (SMA) and Duchenne Muscular Dystrophy (DMD), two of the most common, child onset, rare neuromuscular disorders, present a case study for the translation of preclinical research into clinical work. Over the past decade, well-designed clinical trials and innovative methods have led to the approval of several novel therapies for SMA and DMD, with many more in the pipeline. This review discusses several features that must be considered during trial design for neuromuscular diseases, as well as other rare diseases, to maximise the possibility of trial success using historic examples. These features include well-defined inclusion criteria, matching criteria, alternatives to placebo-controlled trials and the selection of trial endpoints. These features will be particularly important in the coming years as the investigation into innovative therapy approaches for neuromuscular diseases continues.

Compliance to DMD Care Considerations in the Netherlands

BACKGROUND AND OBJECTIVE

To optimize care for patients with DMD, it is essential to know to what extent current care complies with the recommended monitoring frequencies suggested by the DMD care considerations. The objective of this study was to investigate the current care for patients with DMD in the Netherlands and to what extent the care complies with the international care considerations.

METHODS

A cross-sectional questionnaire was carried out among the Dutch DMD patients and caregivers about the patients' functional and health status, visits to healthcare professionals, clinical tests and assessments, therapy, medication use and access to medical aids and devices. Compliance to guidelines was defined by comparing the frequency of visits to health care providers and clinical tests with the recommended frequencies derived from the care considerations of 2010.

RESULTS

Eighty-four participants completed the questionnaire. The majority of participants met the recommended visit frequencies to a neuromuscular specialist and cardiologist. Compliance was suboptimal for respiratory assessments in the non-ambulatory phase, monitoring of side effects of corticosteroid use and neuromuscular assessments. Disease specific information supply was perceived as sufficient and participants were satisfied with the received care.

CONCLUSIONS

This study identifies areas in which compliance is lacking. Countries, such as the Netherlands, working according to a shared care system require easy and low-threshold communication between health care centers and a clear division of roles and responsibilities to reach optimal compliance. In the Netherlands the Duchenne Center Netherlands has the coordinating role.

Genotype characterization and delayed loss of ambulation by glucocorticoids in a large cohort of patients with Duchenne muscular dystrophy

Background

Duchenne muscular dystrophy (DMD) is the most common genetic muscle disease in human. We aimed to describe the genotype distribution in a large cohort of Chinese DMD patients and their delayed loss of ambulation by glucocorticoid (GC) treatments. This is to facilitate protocol designs and outcome measures for the emerging DMD clinical trials.

Results

A total of 1163 patients with DMD were recruited and genotyped. Genotype variations were categorized as large deletions, large duplications, and small mutations. Large deletions were further analyzed for those amenable to exon-skipping therapies. Participants aged 5 years or older were grouped into GC-treated and GC-naïve groups. Clinical progression among different genotypes and their responses to GC treatments were measured by age at loss of ambulation (LOA). Among the mutation genotypes, large deletions, large duplications, and small mutations accounted for 68.79%, 7.14%, and 24.07%, respectively. The mean age at diagnosis was 4.59 years; the median ages at LOA for the GC-naïve, prednisone/prednisolone-treated, and deflazacort-treated groups were 10.23, 12.02, and 13.95 years, respectively. The “deletion amenable to skipping exon 44” subgroup and the nonsense-mutation subgroup had older ages at LOA than the “other deletions” subgroup. Subgroups were further analyzed by both genotypes and GC status. All genotypes showed significant beneficial responses to GC treatment. Deletions amenable to skipping exon 44 showed a lower hazard ratio (0.155). The mean age at death was 18.57 years in this DMD group.

Conclusion

Genotype variation influences clinical progression in certain DMD groups. Beneficial responses to GC treatment were observed among all DMD genotypes. Compared with other genotypes, deletions amenable to skipping exon 44 had a lower hazard ratio, which may indicate a stronger protective effect of GC treatments on this subgroup. These data are valuable for designing future clinical trials, as clinical outcomes may be influenced by the genotypes.

Exon skipping in Duchenne Muscle dystrophy due to a silent p.Ser443= mutation in the DMD gene

Duchenne Muscle dystrophy (DMD) is a X-linked inherited disease predominantly caused by severe mutations in DMD gene leading to absence of dystrophin protein. Here we report a 14-year-old Mongolian boy suffering from proximal muscle weakness, pseudohypertrophic deltoid and gastrocnemius muscles since early childhood. Lactate dehydrogenase (LDH) and creatine kinase (CK) levels were elevated. Mutation analysis including MLPA and sequencing of the DMD gene revealed a hemizygous silent variant, c.1329C>T (p.Ser443=) in exon 11. This silent mutation, listed in the SNP database (rs1060502631), was described as a variant of unknown significance (VUS) in ClinVar database. cDNA analysis demonstrated partial skipping of exon 11 due to this mutation. Although silent mutations are usually considered non-pathogenic, our case emphasizes that silent mutations can be potentially pathogenic. Hence, if silent variants are not annotated in database or not known to be benign, they should be analysed further at cDNA level.

Molecular and Clinical Characteristics of a National Cohort of Paediatric Duchenne Muscular Dystrophy Patients in Norway

BACKGROUND

As new gene-related treatment options for Duchenne muscular dystrophy (DMD) are being developed, precise information about the patients' genetic diagnosis and knowledge about the diversities of natural history in DMD is vital.

OBJECTIVE

To obtain detailed insight into the genetic and clinical characteristics of paediatric DMD in Norway.

METHODS

94 boys with DMD, aged 0-18 years, were identified over a period of 3.5 years, yielding a national prevalence of 13.5×10-5 boys. 73 boys (78%) were recruited to full genetic and clinical or limited (genetic only) evaluation.

RESULTS

Molecular analysis disclosed 64% deletions, 18% duplications and 18% point mutations. The mean age of diagnosis was 3.9±2.0 years. 78% were treated with glucocorticoids from age 5.8±1.5 years. 23 boys (35%) had lost ambulation at an age of 10.7±2.0 years. 17% were treated for left ventricular dysfunction from age 12.1±3.0 years and 12% had received night-time non-invasive positive pressure ventilation from age 13.0±2.5 years.

CONCLUSIONS

The distribution of mutation types and sites was similar to previous studies but with more duplications and fewer point mutations. Any genotype-phenotype correlations were not uncovered. The boys were diagnosed early but there is still diagnostic delay among boys presenting with late motor development. Glucocorticoid treatment was widespread, especially among the younger boys. The clinical results of this comprehensive nationwide study highlight the large variability of disease progression in DMD.

Delays in diagnosis of Duchenne muscular dystrophy: An evaluation of genotypic and sociodemographic factors

INTRODUCTION

In this study we investigate associations between genotypic and sociodemographic factors and the age of diagnosis of Duchenne muscular dystrophy (DMD).

METHODS

Data were collected from the Duchenne Registry from 2007 to 2019, and then used to assess the impact genotype, race/ethnicity, neighborhood poverty levels, and other sociodemographics factors have on the age of diagnosis of DMD patients without a known family history, using univariate and multivariable linear regression.

RESULTS

The mean age of diagnosis was 4.43 years. Non-Caucasian patients and patients from high-poverty neighborhoods were older at diagnosis (P < .01). Increased year of birth was associated with decreasing age of diagnosis (P < .001). Specific genetic mutation subtypes were associated with later ages of symptom onset and diagnosis (P = .005).

DISCUSSION

After adjusting for genotype and year of birth, the average age of diagnosis was significantly later for traditionally at-risk patients.

Duchenne Muscular Dystrophy Newborn Screening: Evaluation of a New GSP® Neonatal Creatine Kinase-MM Kit in a US and Danish Population

Duchenne muscular dystrophy (DMD/Duchenne) is a progressive X-linked disease and is the most common pediatric-onset form of muscular dystrophy, affecting approximately 1:5000 live male births. DNA testing for mutations in the dystrophin gene confirms the diagnosis of this disorder. This study involves assessment of screening newborns for DMD using an immunoassay for muscle-type (MM) creatine kinase (CK) isoform-the GSP Neonatal CK-MM kit. Comparisons were made with CK activity determination by fluorescence measurement. In addition, the study evaluated the effect of gestational age, age of infant at time of sampling and how stable the CK-MM was over time. This assay discriminates well between normal, unaffected and Duchenne affected populations and is suitable for Duchenne newborn screening.

Chemistry and Pharmacology of Deflazacort: A Novel Bioactive Compound for the Treatment of Duchenne Muscular Dystrophy-A Mini Review

Objective:

Firstly, Deflazacort was synthesized in 1969 and has the structural similarity with cortisol. The present review is an attempt to summarize the updated information related to chemistry and pharmacology of Deflazacort.

Development:

Deflazacort a synthetic compound synthesized by derivatization in the chemical structure of prednisolone with an aim to improve its potency. Deflazacort is under global development with Marathon Pharmaceuticals, was approved by the U.S. Food and Drug Administration in year 2017 to treat patients with Duchenne muscular dystrophy (DMD).

Chemistry and Pharmacology:

DMD is one of the rare and genetic disorders with the symptoms of progressive degeneration of muscle tissue. Chemically, it is deacetylated at position 21 to produce active metabolite 21-desacetyl deflazacort (21-desDFZ), which acts through the glucocorticoid receptor. The predominant side effects are cushingoid appearance, increased appetite, upper respiratory tract infection (URTI), pollakiuria, hirsutism, and nasopharyngitis.

Conclusion:

The present article summarizes the available updated information and work done so far on Deflazacort with special emphasis on its chemistry, pharmacology with detailed mechanism of action, pharmacodynamics, pharmacokinetics, metabolism and clinical trials etc.

Clinical management of Duchenne muscular dystrophy: the state of the art

INTRODUCTION

Duchenne muscular dystrophy (DMD) is a devastating, progressive neuromuscular disorder for which there is no cure. As the dystrophin gene is located on the X chromosome, DMD occurs predominately in males. DMD is caused by a lack of functional dystrophin protein resulting from mutations in the 2.2-Mb DMD gene, whichdisrupts the reading frame. Care considerations for DMD advocate a coordinated, multidisciplinary approach to the management of DMD in order to optimize management of the primary manifestations of DMD as well as any secondary complications that may arise.

METHODS

This review provides an overview of the multidisciplinary clinical management of DMD with regard to the respiratory, cardiology, orthopedic, and nutritional needs of patients with DMD. Recent advances in novel disease-modifying treatments for DMD are also discussed with specific reference to exon skipping and suppression of premature stop codons as promising genetic therapies.

RESULTS

The combination of multidisciplinary clinical management alongside novel gene therapiesoffers physicians a powerful armamentarium for the treatment of DMD.

Critical Assessment of the mdx Mouse with Ex Vivo Eccentric Contraction of the Diaphragm Muscle

Muscle function and health progressively deteriorate during the progression of muscle dystrophies. The ability to objectively characterize muscle function and muscle damage is useful not only when comparing variants of dystrophy models, but also for characterizing the effects of interventions aiming to improve or halt the progressive decline of muscle function and muscle health. The protocols in this chapter describe the use of ex vivo eccentric contraction of the diaphragm muscle as a measure of muscle susceptibility to damage. Because muscle has a robust regenerative capacity, unhealthy muscle may be functionally close to normal; therefore, protocols for ex vivo characterization of muscle are often essential for assessing the effects of interventions. Additional methods that can be applied for assessment of dystrophic muscle are also highlighted. © 2018 by John Wiley & Sons, Inc.

Is There a Delay in Diagnosis of Duchenne Muscular Dystrophy Among Preterm-Born Males?

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.

Exon skipping for Duchenne muscular dystrophy: a systematic review and meta-analysis

BACKGROUND

Exon skipping has been considered a promising therapeutic approach for Duchenne muscular dystrophy (DMD). Eteplirsen received conditional approval in the United States in 2016. To date, no systematic reviews or meta-analyses of randomized controlled trials (RCTs) of exon skipping drugs have been published to determine the pooled estimates for the effect of exon skipping in treating DMD.

METHODS

A systematic review and meta-analysis of double-blind RCTs comparing exon-skipping drugs with placebo in DMD was performed. Trials were identified by searching published and unpublished studies from electronically available databases and clinical trial registries through October 2017. The primary outcomes were changes in the 6-min walk test (6MWT) distance, North Star Ambulatory Assessment (NSAA) scores, and adverse events. Random-effects meta-analysis and assessment of risk of bias were performed. This systematic review was registered at PROSPERO (CRD42016037504).

RESULTS

Five studies involving 322 participants were included, investigating eteplirsen in one and drisapersen in four studies. There were no changes in 6MWT distance (mean difference [MD] - 9.16, 95% confidence interval [CI] - 21.94 to 3.62) or NSAA scores (MD 1.20, 95% CI - 2.35 to 4.75) after 24 weeks of treatment in the exon-skipping group compared with placebo. Subgroup analysis for a 6 mg/kg weekly injection of drisapersen showed significant changes in the 6MWT, favoring drisapersen after 24 weeks (MD - 20.24; 95% CI - 39.59 to - 0.89). However, drisapersen resulted in a significant increase in injection site reactions (risk ratio [RR] 3.67, 95% CI 1.96 to 6.89, p < 0.0001) and renal toxicity (RR 1.81, 95% CI 1.11 to 2.94, p = 0.02). Risk of bias was high in two of the five studies, including the eteplirsen and one drisapersen study.

CONCLUSIONS

Current available data do not show evidence that exon-skipping drugs are effective in DMD. Despite potential effectiveness when used at a specific dose, significant side effects were reported with drisapersen. The small number of RCTs with relatively small numbers of participants indicate the difficulty in conducting sufficiently powered studies of DMD. Prospectively planned meta-analysis and utilization of the real-world data may provide a more precise estimate of the effect of exon skipping in this disease.

Prevalence of muscular dystrophy in patients with muscular disorders in Tehran, Iran

Muscular dystrophy is a group of diseases that is characterized by progressive muscle wasting and the weakness of variable distribution and severity. On the basis of the distribution of predominant muscle weakness, there are many different kinds of muscular dystrophy. Some dystrophies are especially frequent in certain populations. There are no studies on the prevalence of muscular dystrophy in Iran. This study was aimed to survey the prevalence of muscular dystrophy among Iranian patients with muscular disorders. This analytical cross-sectional study was conducted on 1000 patients with musculoskeletal disorders who visited the dystrophy association of Bou-Ali Hospital (Tehran) from June 2014 to June 2016. Patients’ data were extracted using a checklist that included age, gender, age of onset, family history, findings from clinical diagnostic tests and types of muscular dystrophy. The clinical findings were the results of genetic tests; EMG-NCV; para-clinical findings, including LDH and CPK; and pathological findings. All data were analyzed by SPSS V.22 (IBM Inc., NY) with Chi Square and One way ANOVA tests. All analyses were performed with P = 0.05 considered as the threshold of statistical significant. Out of the 337 patients studied, 262 (77.7%) were male and 75 (22.3%) were female. Subjects had a mean (± SD) age of 26.08 (± 11.86) years with an age range of 3 to 59 years. The most common types of muscular dystrophy were found to be Duchenne dystrophy (131 cases, 38.9%), limb-girdle dystrophy (91 cases, 27%), Becker dystrophy (58 cases, 17.2%), FSHD dystrophy (31 cases, 9.2%), and SMA (26 cases, 7.7%), respectively. The results showed that a statistically significant relationship between dystrophy types and gender, age, family history, age of diagnosis, CPK and LDH levels (P < 0.001). There were no statistical relationship between dystrophy types and pathological findings (P = 0.57), EMG-NCV test results (P = 0.062), and genetic findings (P = 0.06). Since muscular dystrophies often appear during the first decade of life, any information in regard to their prevalence can contribute to better planning and provisioning of required services, as well as better treatment or control of the condition. The results also showed that genetic tests, para-clinical tests, pathology analysis, and EMG-NCV tests can serve as good diagnostic tools for different varieties of dystrophy. Thus, facilitation of these diagnostic tests, particularly the genetic tests, can lead to a faster and more accurate diagnosis of dystrophy, especially in people with a family history of the disease.

European Cross-Sectional Survey of Current Care Practices for Duchenne Muscular Dystrophy Reveals Regional and Age-Dependent Differences

Background: Publication of comprehensive clinical care guidelines for Duchenne muscular dystrophy (DMD) in 2010 was a milestone for DMD patient management. Our CARE-NMD survey investigates the neuromuscular, medical, and psychosocial care of DMD patients in Europe, and compares it to the guidelines.

Methods: A cross-sectional survey of 1677 patients contacted via the TREAT-NMD patient registries was conducted using self-report questionnaires in seven European countries.

Results: Survey respondents were 861 children and 201 adults. Data describe a European DMD population with mean age of 13.0 years (range 0.8–46.2) of whom 53% had lost ambulation (at 10.3 years of age, median). Corticosteroid medication raised the median age for ambulatory loss from 10.1 years in patients never medicated to 11.4 years in patients who received steroids (p < 0.0001). The majority of patients reported receiving care in line with guidelines, although we identified significant differences between countries and important shortcomings in prevention and treatment. Summarised, 35% of patients aged≥ nine years received no corticosteroid medication, 24% of all patients received no regular physiotherapy, echocardiograms were not performed regularly in 22% of patients, pulmonary function was not regularly assessed in 71% of non-ambulatory patients. Patients with regular follow-up by neuromuscular specialists were more likely to receive care according to guidelines, were better satisfied, and experienced shorter unplanned hospitalization periods.

Consensus on the diagnosis, treatment and follow-up of patients with Duchenne muscular dystrophy

INTRODUCTION

Duchenne muscular dystrophy (DMD) is the most common myopathy in children, with a worldwide prevalence of approximately 0.5 cases per 10,000 male births. It is characterised by a progressive muscular weakness manifesting in early childhood, with the subsequent appearance of musculoskeletal, respiratory, and cardiac complications, causing disability, dependence, and premature death. Currently, DMD is mainly managed with multidisciplinary symptomatic treatment, with favourable results in terms of the progression of the disease. It is therefore crucial to establish clear, up-to-date guidelines enabling early detection, appropriate treatment, and monitoring of possible complications.

DEVELOPMENT

We performed a literature search of the main biomedical databases for articles published in the last 10years in order to obtain an overview of the issues addressed by current guidelines and to identify relevant issues for which no consensus has yet been established. The degree of evidence and level of recommendation of the information obtained were classified and ordered according to the criteria of the American Academy of Neurology.

CONCLUSIONS

DMD management should be multidisciplinary and adapted to the patient's profile and the stage of clinical progression. In addition to corticotherapy, treatment targeting gastrointestinal, respiratory, cardiac, and orthopaedic problems, as well as physiotherapy, should be provided with a view to improving patients' quality of life. Genetic studies play a key role in the management of the disease, both in detecting cases and potential carriers and in characterising the mutation involved and developing new therapies.

A Historical and Current Review of Newborn Screening for Neuromuscular Disorders From Around the World: Lessons for the United States

BACKGROUND

We aimed to review the history of newborn screening for three neuromuscular disorders (Duchenne muscular dystrophy, Pompe disease, and spinal muscular atrophy [SMA]) to determine best practices.

METHODS

The history of newborn screening for Duchenne muscular dystrophy began in 1975 with the measurement of creatinine kinase on newborn male blood spots from two Midwestern hospitals in the United States. Over the next 40 years, ten programs were implemented around the globe although none currently remain. The first experimental pilot program for Pompe disease began in 2005 in Taiwan. In 2013, Missouri was the first US state to implement Pompe newborn screening before its inclusion in the Recommended Uniform Screening Panel (RUSP) in 2015 by the Advisory Committee on Heritable Disorders in Newborns and Children (United States). In 2008, SMA was reviewed and rejected for inclusion in the RUSP because no treatment existed. With the approval of nusinersen in late 2016, spinal muscular atrophy is being reconsidered for the RUSP.

RESULTS

A condition should meet public health screening criteria to be included in the RUSP. Duchenne muscular dystrophy, Pompe, and SMA challenge traditional screening criteria: Duchenne muscular dystrophy does not present in infancy and lacks effective treatment; Pompe and SMA may not present until adulthood; and safety and efficacy of long-term intrathecal treatment for SMA is unknown. Potential reproductive benefit and improved research recruitment do not justify a public health screening program.

CONCLUSIONS

This review provides lessons that could benefit US public health departments as they consider expanding screening to include neuromuscular disorders like Duchenne muscular dystrophy, Pompe, and SMA.

Brazilian consensus on Duchenne muscular dystrophy. Part 1: diagnosis, steroid therapy and perspectives

ABSTRACT Significant advances in the understanding and management of Duchenne muscular dystrophy (DMD) took place since international guidelines were published in 2010. Our objective was to provide an evidence-based national consensus statement for multidisciplinary care of DMD in Brazil. A combination of the Delphi technique with a systematic review of studies from 2010 to 2016 was employed to classify evidence levels and grade of recommendations. Our recommendations were divided in two parts. We present Part 1 here, where we describe the guideline methodology and overall disease concepts, and also provide recommendations on diagnosis, steroid therapy and new drug treatment perspectives for DMD. The main recommendations: 1) genetic testing in diagnostic suspicious cases should be the first line for diagnostic confirmation; 2) patients diagnosed with DMD should have steroids prescribed; 3) lack of published results for phase 3 clinical trials hinders, for now, the recommendation to use exon skipping or read-through agents.

Toe Walking: When Do We Need to Worry?

Toe walking refers to the lack of heel strike during the stance phase of the gait cycle. It is a common variation of normal gait development in children. Persistent toe walking past 2-3 years of age warrants further evaluation as toe walking can be associated with cerebral palsy, muscular dystrophy, and autism spectrum disorders. The diagnosis of idiopathic toe walking is a diagnosis of exclusion used for children with persistent toe walking and no associated medical condition. Despite variable pathophysiology, the treatment of toe walking has similarities across diagnoses as it is focused on the maintenance of range of motion through the ankle.

The golden retriever model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked disease caused by mutations in the DMD gene and loss of the protein dystrophin. The absence of dystrophin leads to myofiber membrane fragility and necrosis, with eventual muscle atrophy and contractures. Affected boys typically die in their second or third decade due to either respiratory failure or cardiomyopathy. Despite extensive attempts to develop definitive therapies for DMD, the standard of care remains prednisone, which has only palliative benefits. Animal models, mainly the mdx mouse and golden retriever muscular dystrophy (GRMD) dog, have played a key role in studies of DMD pathogenesis and treatment development. Because the GRMD clinical syndrome is more severe than in mice, better aligning with the progressive course of DMD, canine studies may translate better to humans. The original founder dog for all GRMD colonies worldwide was identified in the early 1980s before the discovery of the DMD gene and dystrophin. Accordingly, analogies to DMD were initially drawn based on similar clinical features, ranging from the X-linked pattern of inheritance to overlapping histopathologic lesions. Confirmation of genetic homology between DMD and GRMD came with identification of the underlying GRMD mutation, a single nucleotide change that leads to exon skipping and an out-of-frame DMD transcript. GRMD colonies have subsequently been established to conduct pathogenetic and preclinical treatment studies. Simultaneous with the onset of GRMD treatment trials, phenotypic biomarkers were developed, allowing definitive characterization of treatment effect. Importantly, GRMD studies have not always substantiated findings from mdx mice and have sometimes identified serious treatment side effects. While the GRMD model may be more clinically relevant than the mdx mouse, usage has been limited by practical considerations related to expense and the number of dogs available. This further complicates ongoing broader concerns about the poor rate of translation of animal model preclinical studies to humans with analogous diseases. Accordingly, in performing GRMD trials, special attention must be paid to experimental design to align with the approach used in DMD clinical trials. This review provides context for the GRMD model, beginning with its original description and extending to its use in preclinical trials.

State-Of-The-Art Advances in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe and fatal muscle condition affecting young children. Without interventions, affected boys lose the ability to walk independently by the age of 10 and develop progressive cardiac and respiratory failure. The last 20 years have seen a change in the natural history of DMD following improvements in clinical care and proactive interventions to manage complications of the disease. An international collaboration of DMD experts has created care imperatives for best practice in DMD; these are now available in 30 different languages and are disseminated worldwide. An update of these care recommendations is currently under review. More recently, the field has seen encouraging scientific progress in regard to new therapeutic approaches of which a large number are currently being evaluated in clinical trials. With time, improvements in clinical care and access to new treatments and innovations are changing the natural course of DMD, from a relentless progressive illness with death in teenage years to a more chronic illness with a good quality of life and increased life expectancy. This is a particularly encouraging time for DMD, and experiences built in the muscular dystrophy field are likely to be of benefit to the development of new approaches and therapies in other rare diseases.

Ankle-Foot Orthosis in Duchenne Muscular Dystrophy: A 4 year Experience in a Multidisciplinary Neuromuscular Disorders Clinic

OBJECTIVE

To assess Ankle-Foot-Orthosis (AFO) requirement and ambulation in Duchenne Muscular Dystrophy (DMD) patients seen over a period of 4 y at a multi-disciplinary Neuromuscular disorders clinic (NMD).

METHODS

A study was conducted in university quaternary research hospital with DMD patients confirmed by MLPA (multiplex ligation - dependent probe amplification) method and were evaluated between January 2012 and December 2015. Their ambulatory status, detailed neurological and functional status were recorded. Requirement of AFOs was determined and provided.

RESULTS

In total 126 DMD children reported to the NMD clinic. Mean age at presentation was 7.6 y (range 2 to12 y, SD 2.1). Mean duration of illness at first evaluation was 3.4 y (range 0.5 to 10 y, SD 2.0). AFO's were advised at a mean age of 8.5 y (range 7 to 12 y, SD 1.8). Fifty-nine patients were advised AFO as resting or walking splint. At last follow-up 113 patients were still ambulatory whereas 13 had become wheel chair bound. Out of 59 patients, 48 were still wearing AFOs and the remaining discontinued AFOs for various reasons.

CONCLUSIONS

Children with DMD require wearing of AFOs as resting or walking splint, mostly in first or early second decade of life. As there is some gap between onset of clinical signs and requirement of orthosis, follow-up preferably at a multidisciplinary clinic at regular intervals is desirable for timely intervention in the form of AFOs or other splints to prolong ambulatory status in these patients.

Diagnosis of Duchenne Muscular Dystrophy in Italy in the last decade: Critical issues and areas for improvements

Despite all the advances in diagnosis and management of Duchenne muscular dystrophy over the past 50 years, the average age at diagnosis in most countries in the world around is still around 4-5 years. This retrospective study investigates the age at diagnosis in Italy in the past 10 years. We report findings from 384 boys who were diagnosed with DMD from 2005 to 2014. The mean age at first medical contact, which raised the suspicion of DMD, was 31 months. The mean age at diagnosis was 41 months. The finding that more frequently brought to suspect a DMD was the incidental finding of consistent elevated creatine kinase serum level detected during routine assessments in children undergoing general anesthesia or with intercurrent illness. This was followed by motor delay and signs of muscle weakness. Initial concerns were raised by general pediatricians (29%), specialists at tertiary centers (35%) or first level hospitals (23%). In children presenting incidental elevated creatine kinase values the diagnosis was achieved earlier than in children presenting a developmental delay. The mean age at diagnosis in our cohort was about 10-12 months lower than that reported in other countries.

Nutraceuticals and Their Potential to Treat Duchenne Muscular Dystrophy: Separating the Credible from the Conjecture

In recent years, complementary and alternative medicine has become increasingly popular. This trend has not escaped the Duchenne Muscular Dystrophy community with one study showing that 80% of caregivers have provided their Duchenne patients with complementary and alternative medicine in conjunction with their traditional treatments. These statistics are concerning given that many supplements are taken based on purely "anecdotal" evidence. Many nutraceuticals are thought to have anti-inflammatory or anti-oxidant effects. Given that dystrophic pathology is exacerbated by inflammation and oxidative stress these nutraceuticals could have some therapeutic benefit for Duchenne Muscular Dystrophy (DMD). This review gathers and evaluates the peer-reviewed scientific studies that have used nutraceuticals in clinical or pre-clinical trials for DMD and thus separates the credible from the conjecture.

Pharmacological therapy for the prevention and management of cardiomyopathy in Duchenne muscular dystrophy: A systematic review

Cardiomyopathy is a major source of morbidity and mortality in Duchenne muscular dystrophy (DMD) patients now that respiratory care has improved. There is currently no definitive evidence guiding the management of DMD-associated cardiomyopathy (DMD-CM). The objective of this systematic review was to evaluate the effectiveness of pharmacotherapies for the prevention and/or management of DMD-CM and to determine the optimal timing to commence these interventions. A systematic search was conducted in January 2016 using MEDLINE, EMBASE and CINAHL databases and grey literature sources for studies evaluating the use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, beta-blockers or aldosterone antagonists. Study quality assessment was conducted using the Downs and Black quality assessment checklist. PRISMA reporting guidelines were used. Of the 15 studies included in this review, most were of low methodological quality. Meta-analysis was not possible due to heterogeneity of studies. ACE inhibitors, angiotensin receptor blockers, beta-blockers and/or aldosterone antagonists tended to improve or preserve left ventricular systolic function and delay the progression of DMD-CM. While there is evidence supporting the use of heart failure medication in patients with DMD, data regarding these interventions for delaying the onset of DMD-CM and when to initiate therapy are lacking. PROSPERO registration: CRD42015029555.

Duchenne muscular dystrophy: the management of scoliosis

This study summaries the current management of scoliosis in patients with Duchenne Muscular Dystrophy. A literature review of Medline was performed and the collected articles critically appraised. This literature is discussed to give an overview of the current management of scoliosis within Duchenne Muscular Dystrophy. Importantly, improvements in respiratory care, the use of steroids and improving surgical techniques have allowed patients to maintain quality of life and improved life expectancy in this patient group.

Twenty-year follow-up of newborn screening for patients with muscular dystrophy

INTRODUCTION

An opt-out newborn screening (NBS) program for Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) was implemented at 2 hospitals in Pittsburgh, Pennsylvania, between 1987 and 1995.

METHODS

For patients and their parents in families who received a diagnosis of DMD or BMD, either by NBS or by traditional diagnostics after symptom onset, attitudes toward NBS for DMD and BMD were assessed.

RESULTS

All patients and most parents supported NBS for DMD and BMD. In contrast to the NBS parent cohort, the non-NBS cohort felt that diagnosis by NBS would cause anxiety.

CONCLUSIONS

There was strong support of NBS for DMD and BMD in both patients and their parents in families who received a diagnosis through NBS or through traditional diagnostics. No negative psychosocial impacts of NBS were identified among those families who received a diagnosis through NBS.

Ethical and policy issues in newborn screening of children for neurologic and developmental disorders

Genetic testing for neurologic and developmental disorders spans the spectrum from universal newborn screening for conditions like phenylketonuria to diagnostic testing for suspected genetic conditions, to predictive genetic testing for childhood-onset conditions. Given that virtually all children in the United States undergo genetic screening in the newborn period, this article focuses on 3 actual case studies of neurologic and developmental disorders that have been included or proposed for inclusion in newborn screening programs: Duchenne muscular dystrophy (a neuromuscular disorder), Krabbe disease (a neurodegenerative disorder), and fragile X syndrome (a neurodevelopmental disorder).

Pharmacologic management of Duchenne muscular dystrophy: target identification and preclinical trials

Duchenne muscular dystrophy (DMD) is an X-linked human disorder in which absence of the protein dystrophin causes degeneration of skeletal and cardiac muscle. For the sake of treatment development, over and above definitive genetic and cell-based therapies, there is considerable interest in drugs that target downstream disease mechanisms. Drug candidates have typically been chosen based on the nature of pathologic lesions and presumed underlying mechanisms and then tested in animal models. Mammalian dystrophinopathies have been characterized in mice (mdx mouse) and dogs (golden retriever muscular dystrophy [GRMD]). Despite promising results in the mdx mouse, some therapies have not shown efficacy in DMD. Although the GRMD model offers a higher hurdle for translation, dogs have primarily been used to test genetic and cellular therapies where there is greater risk. Failed translation of animal studies to DMD raises questions about the propriety of methods and models used to identify drug targets and test efficacy of pharmacologic intervention. The mdx mouse and GRMD dog are genetically homologous to DMD but not necessarily analogous. Subcellular species differences are undoubtedly magnified at the whole-body level in clinical trials. This problem is compounded by disparate cultures in clinical trials and preclinical studies, pointing to a need for greater rigor and transparency in animal experiments. Molecular assays such as mRNA arrays and genome-wide association studies allow identification of genetic drug targets more closely tied to disease pathogenesis. Genes in which polymorphisms have been directly linked to DMD disease progression, as with osteopontin, are particularly attractive targets.

A mixed methods study of age at diagnosis and diagnostic odyssey for Duchenne muscular dystrophy

The delayed diagnosis of Duchenne muscular dystrophy (DMD) may be an ongoing problem internationally. We aimed to ascertain age at diagnosis and explore parents' experiences of the diagnosis of DMD in Australia. Using mixed methods, data were collected from laboratory and clinical record audits of testing for DMD in Victoria and Tasmania, interviews and a national survey of parents regarding their experiences from first noticing symptoms to receiving a diagnosis. The audits revealed that the median age at diagnosis for DMD was 5 years (n=49 during 2005-2010); this age had not changed substantially over this period. Fourteen parents interviewed reported age at diagnosis ranging from 2 to 8 years with a 6 month to 4 year delay between initial concerns about their child's development and receiving the DMD diagnosis. Sixty-two survey respondents reported the median age at diagnosis was 3 years and 9 months, while the median age when symptoms were noticed was 2 years and 9 months. Parents experienced many emotions in their search for a diagnosis and consulted with a wide range of health professionals. Half the survey respondents felt that their child could have been diagnosed earlier. Despite advances in testing technologies and increasing awareness of DMD, the age at diagnosis has remained constant in Australia. This mixed methods study shows that this diagnostic delay continues to have a negative impact on parents' experiences, places families at risk of having a second affected child and may have a deleterious effect on affected children's treatment.

Improving recognition of Duchenne muscular dystrophy: a retrospective case note review

BACKGROUND

Over the last 30 years, there has been little improvement in the age of diagnosis of Duchenne muscular dystrophy (DMD) (mean age of 4.5-4.11 years).

AIM

To review the diagnostic process for DMD in boys without a family history in order to identify where delays occur and suggest areas for improvement.

DESIGN

A retrospective case note review.

SETTING

A tertiary centre for neuromuscular diseases in England.

PATIENTS

All boys without family history diagnosed with DMD in the last 10 years (n=20).

OUTCOME MEASURES

Mean age at four key steps in the diagnostic pathway of DMD.

RESULTS

(1) Age at first reported symptoms of DMD was 32.5 (8-72) months (2.7 years). (2) First engagement of a healthcare professional was at 42.9 (10-90) months. (3) Creatine kinase (CK) levels were checked at 50.1 (14-91) months. (4) Diagnosis of DMD was confirmed at 51.7 (16-91) months (4.3 years). The total delay from parental concern to diagnosis was 19.2 (4-50) months (1.6 years).

CONCLUSIONS

Our study shows an improvement in the age of diagnosis of DMD although there continues to be a delay in presentation to a health professional and a delay in obtaining a CK test. To reduce these delays, we propose screening for DMD as part of the Child Health Surveillance Programme, in addition to lowering the threshold for CK testing in primary care by promoting a new DMD mnemonic MUSCLE. An earlier diagnosis of DMD will allow timely access to genetic counselling, standards of care and clinical trials.

A mixed methods exploration of families' experiences of the diagnosis of childhood spinal muscular atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease with a carrier frequency of 1 in 41 in Australia. Childhood SMA is classified into three types based on the age at which children present with symptoms and the clinical severity. Families' experiences leading up to the diagnosis have not been described, but are important when considering the potential for a diagnostic odyssey. Using a mixed methods approach, data were collected from interviews and a national survey of families of children with SMA to explore their experiences of this journey. The combined findings (n=28) revealed that the journey to receiving a diagnosis was protracted. The time from first noticing symptoms to finally receiving a diagnosis was emotional and frustrating. Once parents or other family members became aware of symptoms, almost all had consulted with multiple different health professionals before the diagnosis was ultimately made. Not surprisingly, receiving the diagnosis was devastating to the families. The nature of the information and the way it was given to them was not always optimal, particularly because of the difficulties predicting clinical severity. Most felt that their child could have been diagnosed earlier and, although there were mixed views around the benefit of this for their child, they felt it may have reduced the emotional impact on families. Overall, families were more in favour of population carrier screening for SMA when compared with newborn screening of the population. Despite an increasing awareness of SMA, the diagnostic delay continues to have negative impacts on families.

Growth and psychomotor development of patients with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is one of the most common hereditary degenerative neuromuscular diseases and caused by mutations in the dystrophin gene. The objective of the retrospective study was to describe growth and psychomotor development of patients with DMD and to detect a possible genotype-phenotype correlation. Data from 263 patients with DMD (mean age 7.1 years) treated at the Departments of Pediatric Neurology in three German University Hospitals was assessed with respect to body measurements (length, weight, body mass index BMI, head circumference OFC), motor and cognitive development as well as genotype (site of mutation). Anthropometric measures and developmental data were compared to those of a reference population and deviations were analyzed for their frequency in the cohort as well as in relation to the genotypes. Corticosteroid therapy was implemented in 29 from 263 patients. Overall 30% of the patients exhibit a short statue (length < 3rd centile) with onset early in development at 2-5 years of age, and this is even more prevalent when steroid therapy is applied (45% of patients with steroid therapy). The BMI shows a rightwards shift (68% > 50th centile) and the OFC a leftwards shift (65% < 50th centile, 5% microcephaly). Gross motor development is delayed in a third of the patients (mean age at walking 18.3 months, 30% > 18 months, 8% > 24 months). Almost half of the patients show cognitive impairment (26% learning disability, 17% intellectual disability). Although there is no strict genotype-phenotype correlation, particularly mutations in the distal part of the dystrophin gene are frequently associated with short stature and a high rate of microcephaly as well as cognitive impairment.

Methods of standing from supine and percentiles for time to stand and to run 10 meters in young children

OBJECTIVE

To assess the method and time to stand from supine and the time to run 10 m for normal young children.

STUDY DESIGN

Three hundred twenty-one normal children aged 2.8-7.8 years were recruited from primary schools. After standardization, each test was carried out twice, timed, and videoed. The influence of age, sex, height, weight, body mass index (BMI), and method of standing were analyzed. Charts for time to stand and running time were produced and assessment of reproducibility performed.

RESULTS

For the time to stand from supine and the method used, there was a significant correlation with age. More than 50% of young children took >2 seconds. There was no significant association with BMI. Method of standing was associated with standing time in boys but not in girls. A Bland-Altman plot of standing times by 2 observers showed good reproducibility with no clinically significant difference. For the 10-m running test, there was a significant negative correlation with age, height, weight, and BMI.

CONCLUSION

There is considerable variability in the method used and time taken to stand from supine in young children. These change with age, permitting the creation of charts showing age-related normal values.

Newborn bloodspot screening for Duchenne muscular dystrophy: 21 years experience in Wales (UK)

Duchenne muscular dystrophy (DMD), a progressive X-linked neuromuscular disorder, has an estimated worldwide incidence of 1:3500 male births. Currently, there are no curative treatments and the mean age of diagnosis is 5 years. In addition, subsequent pregnancies frequently occur before a diagnosis is made in an index case. An 'opt in' screening programme was introduced in Wales in 1990 with the aim to: reduce the diagnostic delay, permit reproductive choice and allow planning of the care of the affected boy. Newborn bloodspots were collected routinely as part of the Wales newborn screening programme. Specific consent was obtained for this test separately from the other tests. During the 21-year period, 369,780 bloodspot cards were received from male infants, of these 343,170 (92.8%) were screened using a bloodspot creatine kinase (CK) assay following parental consent. A total of 145 cases had a raised CK activity (≥250 U/l) and at follow-up, at 6-8 weeks of age, 79 cases had a normal serum CK (false-positive rate 0.023%) and 66 cases had an elevated serum CK. DMD was confirmed in 56 cases by genotyping/muscle biopsy studies, Becker muscular dystrophy in 5 cases and other rarer forms of muscular dystrophy in 5 cases. This long-term study has so far identified 13 false-negative cases. The incidence of DMD in Wales of 1:5136 during this period is lower than that of 1:4046 before commencement of screening in Wales. Screening has reduced the diagnostic delay enabling reproductive choice for parents of affected boys and earlier administration of current therapies.

Respiratory management strategies for Duchenne muscular dystrophy: practice variation amongst Canadian sub-specialists

PURPOSE

Respiratory management of Duchenne muscular dystrophy (DMD) is not well studied and may vary across centers and practitioners. Our objective was to describe and compare the respiratory management practices of Canadian Pediatric Respirologists and Neuromuscular specialists for children with DMD.

METHODS

A web-based survey was sent to all 56 practicing Canadian Pediatric Respirologists and to all 24 members of the Canadian Pediatric Neuromuscular Group (CPNG) who follow children with neuromuscular diseases. The survey included 28 questions about timing and indications for respiratory consultation, sleep disordered breathing (SDB) assessments, and treatments.

RESULTS

Thirty eight (68%) pediatric respirologists and 17 (71%) CPNG members responded. Respirologists provide initial consultation after a patient's first admission to hospital with respiratory complications (14/38, 37%) and when symptoms of SDB are present (14/38, 37%). Half of the CPNG members request initial Respirology consultation at the time of DMD diagnosis. Both groups request routine pulmonary function tests. Ninety-six percent of respirologists use maximal inspiratory (MIP) and expiratory pressures (MEP) to assess respiratory muscle strength, whereas 82% of CPNG members additionally use peak cough flow. Assessment for SDB is requested by both groups when pulmonary function is abnormal or patients are symptomatic. Respirologists favor polysomnography, whereas CPNG members use overnight pulse oximetry. Nocturnal non-invasive ventilation and lung volume recruitment (LVR) are used in a minority of patients.

CONCLUSIONS

Respirologists and CPNG members provide similar respiratory management of DMD patients, but differ in timing of consultation and choice of tests for pulmonary function and SDB. Canadian practices differ from the American Thoracic Society and Centre for Disease Control guidelines.

[Two cases of Duchenne muscular dystrophy over 40 years after onset]

We report two 45 year old men with Duchenne muscular dystrophy. Case 1 showed a deleted exon 50 of the dystrophin gene by MLPA analysis, and Case 2 showed deleted exons 46-52. Both patients presented with severe weakness of the skeletal muscles and respiratory dysfunction, while cardiac involvement was mild and cognitive function was almost normal. The patients are able to shop at a mall, participate in activities, and attend hobbies, although they are bedridden with artificial respiration through tracheotomy. With the progress of the respiratory care and cardiac protective therapy, the prognosis of Duchenne muscular dystrophy has improved remarkably. At present, it is possible to survive over 40 years with maintenance of quality of life, if cardiac damage is not severe.

Inherited neuromuscular disorders: pathway to diagnosis

Muscle weakness in childhood can be caused by a lesion at any point extending from the motor cortex, brainstem and spinal cord to the anterior horn cell, peripheral nerve, neuromuscular junction and muscle. A comprehensive history and physical examination is essential to aid classification of the neuromuscular disorder and direct gene testing. The more common disorders such as spinal muscular atrophy, Duchenne muscular dystrophy, myotonic dystrophy and facioscapulohumeral dystrophy may be diagnosed on direct gene testing based on the history and clinical examination. The congenital myopathies are classified based on structural abnormalities on muscle biopsy, while protein abnormalities on immunohistochemistry and immunoblotting aid classification of the muscular dystrophies. In this review, we provide an approach to diagnosis of a child with weakness, with a focus on the inherited neuromuscular disorders, and the features on history, examination and investigation that help to distinguish between them.