TeleNEwCARe: An Italian case-control telegenetics study in patients with Hereditary NEuromuscular and CArdiac diseases

Telemedicine provides healthcare services remotely and represents a fundamental resource for the management of rare and fragile patients. Tele-health implementation is a main objective of the European Reference Networks (ERNs) mission to accelerate diagnosis for rare diseases. TeleNewCAre is a pilot case-control project which evaluates the efficacy and satisfaction of telegenetics for neuromuscular and cardiac adult patients, compared to face-to-face genetic counselling. The virtual sessions were co-hosted by a medical geneticist and a neurologist/cardiologist. Specific questionnaires (Clinical Genetics Satisfaction Questionnaire (CGS), Telemedicine Satisfaction Questionnaire (TSQ) and a Satisfaction Questionnaire for medical geneticists) were used to assess the effectiveness and fulfilment of telecounselling, both for patients and health care providers. Satisfaction expressed for telegenetics did not significantly differ from face-to-face counselling. The virtually enrolled patients declared they had the possibility to relate confidentially with the specialists, to share information and to be informed in an exhaustive way about their disease. Almost all patients declared themselves willing to reuse the telecounselling in the future. The multidisciplinary care was perceived as a significant added value. No overt technical problems were reported although the need for digital skills and tools can limit patients' compliance. Our experience supports telegenetics as a valid alternative to traditional genetic counselling in cardiac and neuromuscular patients. This innovative approach facilitates multidisciplinary care, grants a periodical follow up, without forcing patients to discomfortable travelling, and allows to maintain expert care. This result meets the ERNs needs to reduce patients' burden to access and monitor their healthcare.

Academic achievement and needs of school-aged children born with selected congenital anomalies: A systematic review and meta-analysis

Children with congenital anomalies have poorer intellectual and cognitive development compared to their peers, but evidence for academic achievement using objective measures is lacking. We aimed to summarize and synthesize evidence on academic outcomes and special education needs (SEN) of school‐aged children born with selected major structural congenital anomalies. Electronic databases (MEDLINE, EMBASE, Scopus, PsycINFO, CINAHL, ProQuest Natural Science and Education Collections), reference lists and citations for 1990–2020 were systematically searched. We included original‐research articles on academic achievement in children with non‐syndromic congenital anomalies that involved school test results, standardized tests and/or SEN data. Random‐effects meta‐analyses were performed to estimate pooled mean test scores in mathematics and/or reading where possible and pooled odds ratios (ORs) for SEN in children with severe congenital heart defects (CHDs) and children with orofacial clefts (OFCs). Thirty‐nine eligible studies (n = 21,066 children) were synthesized narratively. Sixteen studies were included in meta‐analyses. Children with non‐syndromic congenital anomalies were at a higher risk of academic underachievement than controls across school levels. Children with severe CHD (pooled OR = 2.32, 95% CI: 1.90, 2.82), and children with OFC (OR = 1.38 (95% CI: 1.20, 1.57), OR = 3.07 (95% CI: 2.65, 3.56), and OR = 3.96 (95% CI: 3.31, 4.72) for children with cleft lip, cleft palate and cleft lip/palate, respectively) had significantly higher ORs for SEN than controls. Children with non‐syndromic congenital anomalies underperform academically and have higher SEN rates compared to their peers. Early monitoring and development of differential SEN are important to promote academic progress in these children.

Circadian Genes as Exploratory Biomarkers in DMD: Results From Both the mdx Mouse Model and Patients

Duchenne muscular dystrophy (DMD) is a rare genetic disease due to dystrophin gene mutations which cause progressive weakness and muscle wasting. Circadian rhythm coordinates biological processes with the 24-h cycle and it plays a key role in maintaining muscle functions, both in animal models and in humans. We explored expression profiles of circadian circuit master genes both in Duchenne muscular dystrophy skeletal muscle and in its animal model, the mdx mouse. We designed a customized, mouse-specific Fluidic-Card-TaqMan-based assay (Fluid-CIRC) containing thirty-two genes related to circadian rhythm and muscle regeneration and analyzed gastrocnemius and tibialis anterior muscles from both unexercised and exercised mdx mice. Based on this first analysis, we prioritized the 7 most deregulated genes in mdx mice and tested their expression in skeletal muscle biopsies from 10 Duchenne patients. We found that CSNK1E, SIRT1, and MYOG are upregulated in DMD patient biopsies, consistent with the mdx data. We also demonstrated that their proteins are detectable and measurable in the DMD patients’ plasma. We suggest that CSNK1E, SIRT1, and MYOG might represent exploratory circadian biomarkers in DMD.

Functional Characterization of Two Novel Mutations in SCN5A Associated with Brugada Syndrome Identified in Italian Patients

Background. Brugada syndrome (BrS) is an autosomal dominantly inherited cardiac disease characterized by “coved type” ST-segment elevation in the right precordial leads, high susceptibility to ventricular arrhythmia and a family history of sudden cardiac death. The SCN5A gene, encoding for the cardiac voltage-gated sodium channel Nav1.5, accounts for ~20–30% of BrS cases and is considered clinically relevant. Methods. Here, we describe the clinical findings of two Italian families affected by BrS and provide the functional characterization of two novel SCN5A mutations, the missense variant Pro1310Leu and the in-frame insertion Gly1687_Ile1688insGlyArg. Results. Despite being clinically different, both patients have a family history of sudden cardiac death and had history of arrhythmic events. The Pro1310Leu mutation significantly reduced peak sodium current density without affecting channel membrane localization. Changes in the gating properties of expressed Pro1310Leu channel likely account for the loss-of-function phenotype. On the other hand, Gly1687_Ile1688insGlyArg channel, identified in a female patient, yielded a nearly undetectable sodium current. Following mexiletine incubation, the Gly1687_Ile1688insGlyArg channel showed detectable, albeit very small, currents and biophysical properties similar to those of the Nav1.5 wild-type channel. Conclusions. Overall, our results suggest that the degree of loss-of-function shown by the two Nav1.5 mutant channels correlates with the aggressive clinical phenotype of the two probands. This genotype-phenotype correlation is fundamental to set out appropriate therapeutical intervention.

Separatrix crossing and symmetry breaking in NLSE-like systems due to forcing and damping

We theoretically and experimentally examine the effect of forcing and damping on systems that can be described by the nonlinear Schrödinger equation (NLSE), by making use of the phase-space predictions of the three-wave truncation. In the latter, the spectrum is truncated to only the fundamental frequency and the upper and lower sidebands. Our experiments are performed on deep water waves, which are better described by the higher-order NLSE, the Dysthe equation. We therefore extend our analysis to this system. However, our conclusions are general for NLSE systems. By means of experimentally obtained phase-space trajectories, we demonstrate that forcing and damping cause a separatrix crossing during the evolution. When the system is damped, it is pulled outside the separatrix, which in the real space corresponds to a phase-shift of the envelope and therefore doubles the period of the Fermi-Pasta-Ulam-Tsingou recurrence cycle. When the system is forced by the wind, it is pulled inside the separatrix, lifting the phase-shift. Furthermore, we observe a growth and decay cycle for modulated plane waves that are conventionally considered stable. Finally, we give a theoretical demonstration that forcing the NLSE system can induce symmetry breaking during the evolution.

Long-term survival of children born with congenital anomalies: A systematic review and meta-analysis of population-based studies

BACKGROUND

Following a reduction in global child mortality due to communicable diseases, the relative contribution of congenital anomalies to child mortality is increasing. Although infant survival of children born with congenital anomalies has improved for many anomaly types in recent decades, there is less evidence on survival beyond infancy. We aimed to systematically review, summarise, and quantify the existing population-based data on long-term survival of individuals born with specific major congenital anomalies and examine the factors associated with survival.

METHODS AND FINDINGS

Seven electronic databases (Medline, Embase, Scopus, PsycINFO, CINAHL, ProQuest Natural, and Biological Science Collections), reference lists, and citations of the included articles for studies published 1 January 1995 to 30 April 2020 were searched. Screening for eligibility, data extraction, and quality appraisal were performed in duplicate. We included original population-based studies that reported long-term survival (beyond 1 year of life) of children born with a major congenital anomaly with the follow-up starting from birth that were published in the English language as peer-reviewed papers. Studies on congenital heart defects (CHDs) were excluded because of a recent systematic review of population-based studies of CHD survival. Meta-analysis was performed to pool survival estimates, accounting for trends over time. Of 10,888 identified articles, 55 (n = 367,801 live births) met the inclusion criteria and were summarised narratively, 41 studies (n = 54,676) investigating eight congenital anomaly types (spina bifida [n = 7,422], encephalocele [n = 1,562], oesophageal atresia [n = 6,303], biliary atresia [n = 3,877], diaphragmatic hernia [n = 6,176], gastroschisis [n = 4,845], Down syndrome by presence of CHD [n = 22,317], and trisomy 18 [n = 2,174]) were included in the meta-analysis. These studies covered birth years from 1970 to 2015. Survival for children with spina bifida, oesophageal atresia, biliary atresia, diaphragmatic hernia, gastroschisis, and Down syndrome with an associated CHD has significantly improved over time, with the pooled odds ratios (ORs) of surviving per 10-year increase in birth year being OR = 1.34 (95% confidence interval [95% CI] 1.24-1.46), OR = 1.50 (95% CI 1.38-1.62), OR = 1.62 (95% CI 1.28-2.05), OR = 1.57 (95% CI 1.37-1.81), OR = 1.24 (95% CI 1.02-1.5), and OR = 1.99 (95% CI 1.67-2.37), respectively (p < 0.001 for all, except for gastroschisis [p = 0.029]). There was no observed improvement for children with encephalocele (OR = 0.98, 95% CI 0.95-1.01, p = 0.19) and children with biliary atresia surviving with native liver (OR = 0.96, 95% CI 0.88-1.03, p = 0.26). The presence of additional structural anomalies, low birth weight, and earlier year of birth were the most commonly reported predictors of reduced survival for any congenital anomaly type. The main limitation of the meta-analysis was the small number of studies and the small size of the cohorts, which limited the predictive capabilities of the models resulting in wide confidence intervals.

CONCLUSIONS

This systematic review and meta-analysis summarises estimates of long-term survival associated with major congenital anomalies. We report a significant improvement in survival of children with specific congenital anomalies over the last few decades and predict survival estimates up to 20 years of age for those born in 2020. This information is important for the planning and delivery of specialised medical, social, and education services and for counselling affected families. This trial was registered on the PROSPERO database (CRD42017074675).

Hypospadias prevalence in the Emilia Romagna Region registry: Increasing or methodology?

INTRODUCTION

Hypospadias is one of the most common congenital anomalies in male infants, defined as incomplete development of the urethra. Despite the wealth of literature, there are conflicting data on the values and trends of prevalence, due to multifactorial origin but often also to methodological differences between studies. The aim of this study was to analyse prevalence, trends and risk factors of hypospadias in the Emilia Romagna Region, Italy.

MATERIAL AND METHODS

The Emilia-Romagna Registry (IMER) is a population-based congenital anomaly database covering the first year of life, active since 1978. IMER uses multi-source ascertainment, including hospital discharge records (SDO) from 2009, through a validated algorithm. From 2014, IMER changed the algorithm, and included all hypospadias identified in SDO, and not only those confirmed by surgery. All cases identified in the IMER database, coded 7526.01-7526.09 or Q54.0-Q54.9 in 2010-2016, were analysed.

RESULT AND DISCUSSION

A total of 604 hypospadias cases were registered among 267,285 births; 526 were isolated, giving a prevalence of 2 per 1000. An increase from 1.6 in 2010 to 2.9 in 2016 was seen. The comparison between consecutive years was not significant neither from 2010 to 2013 nor in the period 2014-2016. There was instead a significant difference between the two periods, suggesting that the ascertainment change in 2014 is probably responsible for the increase. In the last three years analysed, isolated hypospadias prevalence is 2.5 per 1000. In the study period, mother's age over 39 years, multiple birth, preterm birth, small for gestational age, Caucasian compared with Asiatic or Africans were statistically associated with higher hypospadias prevalence. There was no association neither between hypospadias and paternal age nor maternal body mass index or assisted reproductive technology.

CONCLUSION

Whilst hypospadias prevalence trend is debated in the literature, in IMER it seems to be stable, with methodological changes affecting the trends. Risk factors potentially involved in developing hypospadias are environment and population characteristics, so understanding and monitoring hypospadias prevalence remains important.

Single-spectrum prediction of kurtosis of water waves in a nonconservative model

We study statistical properties after a sudden episode of wind for water waves propagating in one direction. A wave with random initial conditions is propagated using a forced-damped higher-order nonlinear Schrödinger equation. During the wind episode, the wave action increases, the spectrum broadens, the spectral mean shifts up, and the Benjamin-Feir index (BFI) and the kurtosis increase. Conversely, after the wind episode, the opposite occurs for each quantity. The kurtosis of the wave height distribution is considered the main parameter that can indicate whether rogue waves are likely to occur in a sea state, and the BFI is often mentioned as a means to predict the kurtosis. However, we find that while there is indeed a quadratic relation between these two, this relationship is dependent on the details of the forcing and damping. Instead, a simple and robust quadratic relation does exist between the kurtosis and the bandwidth. This could allow for a single-spectrum assessment of the likelihood of rogue waves in a given sea state. In addition, as the kurtosis depends strongly on the damping and forcing coefficients, by combining the bandwidth measurement with the damping coefficient, the evolution of the kurtosis after the wind episode can be predicted.

Duchenne Muscular Dystrophy Myogenic Cells from Urine-Derived Stem Cells Recapitulate the Dystrophin Genotype and Phenotype

A ready source of autologous myogenic cells is of vital importance for drug screening and functional genetic studies in Duchenne muscular dystrophy (DMD), a rare disease caused by a variety of dystrophin gene mutations. As stem cells (SCs) can be easily and noninvasively obtained from urine specimens, we set out to determine whether they could be myogenically induced and useful in DMD research. To this end, we isolated stem cells from the urine of two healthy donors and from one patient with DMD, and performed surface marker characterization, myogenic differentiation (MyoD), and then transfection with antisense oligoribonucleotides to test for exon skipping and protein restoration. We demonstrated that native urine-derived stem cells express the full-length dystrophin transcript, and that the dystrophin mutation was retained in the cells of the patient with DMD, although the dystrophin protein was detected solely in control cells after myogenic transformation according to the phenotype. Notably, we also showed that treatment with antisense oligoribonucleotide against dystrophin exon 44 induced skipping in both native and MyoD-transformed urine-derived stem cells in DMD, with a therapeutic transcript-reframing effect, as well as visible protein restoration in the latter. Hence MyoD-transformed cells may be a good myogenic model for studying dystrophin gene expression, and native urine stem cells could be used to study the dystrophin transcript, and both diagnostic procedures and splicing modulation therapies in both patients and control subjects, without invasive and costly collection methods. New, bankable bioproducts from urine stem cells, useful for prescreening studies and therapeutic applications alike, are also foreseeable after further, more in-depth characterization.

Transcriptional and epigenetic analyses of the DMD locus reveal novel cis‑acting DNA elements that govern muscle dystrophin expression

The dystrophin gene (DMD) is the largest gene in the human genome, mapping on the Xp21 chromosome locus. It spans 2.2Mb and accounts for approximately 0,1% of the entire human genome. Mutations in this gene cause Duchenne and Becker Muscular Dystrophy, X-linked Dilated Cardiomyopathy, and other milder muscle phenotypes. Beside the remarkable number of reports describing dystrophin gene expression and the pathogenic consequences of the gene mutations in dystrophinopathies, the full scenario of the DMD transcription dynamics remains however, poorly understood. Considering that the full transcription of the DMD gene requires about 16h, we have investigated the activity of RNA Polymerase II along the entire DMD locus within the context of specific chromatin modifications using a variety of chromatin-based techniques. Our results unveil a surprisingly powerful processivity of the RNA polymerase II along the entire 2.2Mb of the DMD locus with just one site of pausing around intron 52. We also discovered epigenetic marks highlighting the existence of four novel cis‑DNA elements, two of which, located within intron 34 and exon 45, appear to govern the architecture of the DMD chromatin with implications on the expression levels of the muscle dystrophin mRNA. Overall, our findings provide a global view on how the entire DMD locus is dynamically transcribed by the RNA pol II and shed light on the mechanisms involved in dystrophin gene expression control, which can positively impact on the optimization of the novel ongoing therapeutic strategies for dystrophinopathies.

Recessive mutations in MSTO1 cause mitochondrial dynamics impairment, leading to myopathy and ataxia

We report here the first families carrying recessive variants in the MSTO1 gene: compound heterozygous mutations were identified in two sisters and in an unrelated singleton case, who presented a multisystem complex phenotype mainly characterized by myopathy and cerebellar ataxia. Human MSTO1 is a poorly studied protein, suggested to have mitochondrial localization and to regulate morphology and distribution of mitochondria. As for other mutations affecting genes involved in mitochondrial dynamics, no biochemical defects typical of mitochondrial disorders were reported. Studies in patients’ fibroblasts revealed that MSTO1 protein levels were strongly reduced, the mitochondrial network was fragmented, and the fusion events among mitochondria were decreased, confirming the deleterious effect of the identified variants and the role of MSTO1 in modulating mitochondrial dynamics. We also found that MSTO1 is mainly a cytosolic protein. These findings indicate recessive mutations in MSTO1 as a new cause for inherited neuromuscular disorders with multisystem features.

Becker muscular dystrophy due to an intronic splicing mutation inducing a dual dystrophin transcript

We describe a 29-year-old patient who complained of left thigh muscle weakness since he was 23 and of moderate proximal weakness of both lower limbs with difficulty in climbing stairs and running since he was 27. Mild weakness of iliopsoas and quadriceps muscles and muscle atrophy of both the distal forearm and thigh were observed upon clinical examination. He harboured a novel c.1150-3C>G substitution in the DMD gene, affecting the intron 10 acceptor splice site and causing exon 11 skipping and an out-of-frame transcript. However, protein of normal molecular weight but in reduced amounts was observed on Western Blot analysis. Reverse transcription analysis on muscle RNA showed production, via alternative splicing, of a transcript missing exon 11 as well as a low abundant full-length transcript which is enough to avoid the severe Duchenne phenotype. Our study showed that a reduced amount of full length dystrophin leads to a mild form of Becker muscular dystrophy. These results confirm earlier findings that low amounts of dystrophin can be associated with a milder phenotype, which is promising for therapies aiming at dystrophin restoration.

Heteroclinic Structure of Parametric Resonance in the Nonlinear Schrödinger Equation

We show that the nonlinear stage of modulational instability induced by parametric driving in the defocusing nonlinear Schrödinger equation can be accurately described by combining mode truncation and averaging methods, valid in the strong driving regime. The resulting integrable oscillator reveals a complex hidden heteroclinic structure of the instability. A remarkable consequence, validated by the numerical integration of the original model, is the existence of breather solutions separating different Fermi-Pasta-Ulam recurrent regimes. Our theory also shows that optimal parametric amplification unexpectedly occurs outside the bandwidth of the resonance (or Arnold tongues) arising from the linearized Floquet analysis.

Deep RNA profiling identified CLOCK and molecular clock genes as pathophysiological signatures in collagen VI myopathy

Collagen VI myopathies are genetic disorders caused by mutations in collagen 6 A1, A2 and A3 genes, ranging from the severe Ullrich congenital muscular dystrophy to the milder Bethlem myopathy, which is recapitulated by collagen-VI-null (Col6a1(-/-)) mice. Abnormalities in mitochondria and autophagic pathway have been proposed as pathogenic causes of collagen VI myopathies, but the link between collagen VI defects and these metabolic circuits remains unknown. To unravel the expression profiling perturbation in muscles with collagen VI myopathies, we performed a deep RNA profiling in both Col6a1(-/-)mice and patients with collagen VI pathology. The interactome map identified common pathways suggesting a previously undetected connection between circadian genes and collagen VI pathology. Intriguingly, Bmal1(-/-)(also known as Arntl) mice, a well-characterized model displaying arrhythmic circadian rhythms, showed profound deregulation of the collagen VI pathway and of autophagy-related genes. The involvement of circadian rhythms in collagen VI myopathies is new and links autophagy and mitochondrial abnormalities. It also opens new avenues for therapies of hereditary myopathies to modulate the molecular clock or potential gene-environment interactions that might modify muscle damage pathogenesis.

Biochemical characterization of patients with in-frame or out-of-frame DMD deletions pertinent to exon 44 or 45 skipping

IMPORTANCE

In Duchenne muscular dystrophy (DMD), the reading frame of an out-of-frame DMD deletion can be repaired by antisense oligonucleotide (AO)-mediated exon skipping. This creates a shorter dystrophin protein, similar to those expressed in the milder Becker muscular dystrophy (BMD). The skipping of some exons may be more efficacious than others. Patients with exon 44 or 45 skippable deletions (AOs in clinical development) have a less predictable phenotype than those skippable for exon 51, a group in advanced clinical trials. A way to predict the potential of AOs is the study of patients with BMD who have deletions that naturally mimic those that would be achieved by exon skipping.

OBJECTIVE

To quantify dystrophin messenger RNA (mRNA) and protein expression in patients with DMD deletions treatable by, or mimicking, exon 44 or 45 skipping.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective study of nondystrophic controls (n = 2), patients with DMD (n = 5), patients with intermediate muscular dystrophy (n = 3), and patients with BMD (n = 13) at 4 university-based academic centers and pediatric hospitals. Biochemical analysis of existing muscle biopsies was correlated with the severity of the skeletal muscle phenotype.

MAIN OUTCOMES AND MEASURES

Dystrophin mRNA and protein expression.

RESULTS

Patients with DMD who have out-of-frame deletions skippable for exon 44 or 45 had an elevated number of revertant and trace dystrophin expression (approximately 19% of control, using quantitative immunohistochemistry) with 4 of 9 patients presenting with an intermediate muscular dystrophy phenotype (3 patients) or a BMD-like phenotype (1 patient). Corresponding in-frame deletions presented with predominantly mild BMD phenotypes and lower dystrophin levels (approximately 42% of control) than patients with BMD modeling exon 51 skipping (approximately 80% of control). All 12 patients with in-frame deletions had a stable transcript compared with 2 of 9 patients with out-of-frame deletions (who had intermediate muscular dystrophy and BMD phenotypes).

CONCLUSIONS AND RELEVANCE

Exon 44 or 45 skipping will likely yield lower levels of dystrophin than exon 51 skipping, although the resulting protein is functional enough to often maintain a mild BMD phenotype. Dystrophin transcript stability is an important indicator of dystrophin expression, and transcript instability in DMD compared with BMD should be explored as a potential biomarker of response to AOs. This study is beneficial for the planning, execution, and analysis of clinical trials for exon 44 and 45 skipping.

Observation of modulationally unstable multi-wave mixing

We demonstrate experimentally that multiple four-wave mixing (FWM) pumped by a dual-frequency input in a single-mode fiber is modulationally unstable. This collective type of instability leads, in the anomalous dispersion regime, to sideband growth around all orders of FWM. This is in contrast with the normal dispersion regime where our measurements show that FWM exhibits no instability. Our conclusions are based on the first systematic mapping of the phenomenon as a function of the dual-pump input frequency separation.

Genetic characterization in symptomatic female DMD carriers: lack of relationship between X-inactivation, transcriptional DMD allele balancing and phenotype

BACKGROUND

Although Duchenne and Becker muscular dystrophies, X-linked recessive myopathies, predominantly affect males, a clinically significant proportion of females manifesting symptoms have also been reported. They represent an heterogeneous group characterized by variable degrees of muscle weakness and/or cardiac involvement. Though preferential inactivation of the normal X chromosome has long been considered the principal mechanism behind disease manifestation in these females, supporting evidence is controversial.

METHODS

Eighteen females showing a mosaic pattern of dystrophin expression on muscle biopsy were recruited and classified as symptomatic (7) or asymptomatic (11), based on the presence or absence of muscle weakness. The causative DMD gene mutations were identified in all cases, and the X-inactivation pattern was assessed in muscle DNA. Transcriptional analysis in muscles was performed in all females, and relative quantification of wild-type and mutated transcripts was also performed in 9 carriers. Dystrophin protein was quantified by immunoblotting in 2 females.

RESULTS

The study highlighted a lack of relationship between dystrophic phenotype and X-inactivation pattern in females; skewed X-inactivation was found in 2 out of 6 symptomatic carriers and in 5 out of 11 asymptomatic carriers. All females were characterized by biallelic transcription, but no association was found between X-inactivation pattern and allele transcriptional balancing. Either a prevalence of wild-type transcript or equal proportions of wild-type and mutated RNAs was observed in both symptomatic and asymptomatic females. Moreover, very similar levels of total and wild-type transcripts were identified in the two groups of carriers.

CONCLUSIONS

This is the first study deeply exploring the DMD transcriptional behaviour in a cohort of female carriers. Notably, no relationship between X-inactivation pattern and transcriptional behaviour of DMD gene was observed, suggesting that the two mechanisms are regulated independently. Moreover, neither the total DMD transcript level, nor the relative proportion of the wild-type transcript do correlate with the symptomatic phenotype.

Early corticosteroid treatment in 4 Duchenne muscular dystrophy patients: 14-year follow-up

INTRODUCTION

Corticosteroid treatment is the standard of care in Duchenne muscular dystrophy (DMD), but the optimal age to initiate treatment and dosage pattern remain a matter of discussion.

METHODS

We performed a long-term study of alternate-day corticosteroids in five 2- to 4-year-old DMD patients. The primary outcome measure was prolongation of the ability to walk.

RESULTS

One patient lost ambulation at age 10. Four patients, aged 16 to 18 were fully ambulant, and 3 of them could still climb stairs. Respiratory function was moderately reduced in 2. Left ventricular ejection fraction was > 45%. Short stature and delayed puberty were the most relevant side effects. Although the negative impact of corticosteroid treatment on growth rate remained their major concern, parents and patients stated that they preferred corticosteroid therapy.

CONCLUSIONS

Long-term corticosteroid treatment is effective in prolonging function but not in recovering lost function, and its early use seems appropriate.

Dystrophin quantification and clinical correlations in Becker muscular dystrophy: implications for clinical trials

Duchenne muscular dystrophy is caused by mutations in the DMD gene that disrupt the open reading frame and prevent the full translation of its protein product, dystrophin. Restoration of the open reading frame and dystrophin production can be achieved by exon skipping using antisense oligonucleotides targeted to splicing elements. This approach aims to transform the Duchenne muscular dystrophy phenotype to that of the milder disorder, Becker muscular dystrophy, typically caused by in-frame dystrophin deletions that allow the production of an internally deleted but partially functional dystrophin. There is ongoing debate regarding the functional properties of the different internally deleted dystrophins produced by exon skipping for different mutations; more insight would be valuable to improve and better predict the outcome of exon skipping clinical trials. To this end, we have characterized the clinical phenotype of 17 patients with Becker muscular dystrophy harbouring in-frame deletions relevant to on-going or planned exon skipping clinical trials for Duchenne muscular dystrophy and correlated it to the levels of dystrophin, and dystrophin-associated protein expression. The cohort of 17 patients, selected exclusively on the basis of their genotype, included 4 asymptomatic, 12 mild and 1 severe patient. All patients had dystrophin levels of >40% of control and significantly higher dystrophin (P = 0.013), β-dystroglycan (P = 0.025) and neuronal nitric oxide synthase (P = 0.034) expression was observed in asymptomatic individuals versus symptomatic patients with Becker muscular dystrophy. Furthermore, grouping the patients by deletion, patients with Becker muscular dystrophy with deletions with an end-point of exon 51 (the skipping of which could rescue the largest group of Duchenne muscular dystrophy deletions) showed significantly higher dystrophin levels (P = 0.034) than those with deletions ending with exon 53. This is the first quantitative study on both dystrophin and dystrophin-associated protein expression in patients with Becker muscular dystrophy with deletions relevant for on-going exon skipping trials in Duchenne muscular dystrophy. Taken together, our results indicate that all varieties of internally deleted dystrophin assessed in this study have the functional capability to provide a substantial clinical benefit to patients with Duchenne muscular dystrophy.