170th ENMC International Workshop: Bone protection for corticosteroid treated Duchenne muscular dystrophy. 27–29 November 2009, Naarden, The Netherlands

Awareness of bone strength in patients with neuromuscular disorders: ERN EURO-NMD clinician survey and European patient survey

Bone strength is reduced In various neuromuscular disorders (NMDs). We aimed to assess the awareness and practice of bone strength management in NDMs among clinicians and patients. We performed two online surveys; among health care providers (HCPs) of the European Reference Network for Neuromuscular Disorders (ERN EURO-NMD) and among patients. The survey among 52 HCPs showed that awareness of potentially impaired bone strength in people with NMDs was reasonable to good: the vast majority of HCPs asked often or almost always about bone fractures during history-taking (81 %). Bone strength was less often assessed: often or almost always at diagnosis (50 %) and at follow-up (58 %). Medical training on this topic was considered poor to very poor in 50 % of HCPs. Prevention and treatment of reduced bone strength was variable and multidisciplinary care was sub-optimal. The survey among 581 patients provided important additional insights. Many patients were followed-up outside ERN EURO-NMD centers and treatment was variable. These parallel surveys provided a broad view on the awareness and management of bone strength in people with NMDs. The findings are expected to increase the appreciation of this important aspect of NMD care, and direct future research foci and care guidelines.

Reduced bone mineral density in adolescents with Duchenne Muscular Dystrophy (DMD) and scoliosis

Duchenne muscular dystrophy is a progressive disease usually associated with loss of ambulation and progressive scoliosis. Immobilisation and glucocorticoid treatment are predisposing factors for reduced bone mineral density (BMD). Analysis of quantitative computed tomography revealed low BMD in thoracic and lumbar vertebrae in comparison to age- and sex-matched healthy controls.

INTRODUCTION

Evaluation of vertebral bone mineral density (BMD) in Duchenne Muscular Dystrophy (DMD) adolescents with untreated advanced scoliosis and comparison with the BMD values of healthy age-matched controls, based on quantitative computer tomography.

METHODS

Thirty-seven DMD adolescents (age 15.6 ± 2.5 years) with spinal deformity were evaluated clinically and radiologically prior to definite spinal fusion and compared to 31 male and age-matched healthy individuals (age 15.7 ± 2.3 years). Data related to previous medical treatment, physiotherapy and ambulatory status was also analysed. Scoliotic curves were measured on plain sitting radiographs of the spine. The BMD Z-scores of the thoracic and lumbar vertebrae were calculated with QCTpro® (Mindways Software Inc., USA), based on data sets of preoperative, phantom pre-calibrated spinal computed tomography scans.

RESULTS

A statistically significant lower BMD could be found in DMD adolescents, when compared to healthy controls, showing an average value for the lumbar spine of 80.5 ± 30.5 mg/cm³. Z-scores deteriorated from the upper thoracic towards the lower lumbar vertebrae. All but the uppermost thoracic vertebrae had reduced BMD values, with the thoracolumbar and lumbar region demonstrating the lowest BMD. No significant correlation was observed between BMD and the severity of the scoliotic curve, previous glucocorticoid treatment, cardiovascular impairment, vitamin D supplementation, non-invasive ventilation or physiotherapy.

CONCLUSION

DMD adolescents with scoliosis have strongly reduced BMD Z-scores, especially in the lumbar spine in comparison to healthy controls. These findings support the implementation of a standardised screening and treatment protocol. Level of evidence/clinical relevance: therapeutic level III.

The relationship of bone mineral density and vitamin D levels with steroid use and ambulation in patients with Duchenne muscular dystrophy

Objectives

This study aims to assess the bone mineral density (BMD) and serum levels of 25(OH)-vitamin D and their relationship with steroid use and ambulation in patients with Duchenne muscular dystrophy (DMD).

Patients and methods

Between January 2017 and May 2018, medical records of a total of 67 male patients (mean age, 13.9±4.3 years; range, 8 to 25 years) who were diagnosed with definite DMD were retrospectively analyzed. Demographic data, functional activity level, steroid use, fracture history and location, serum levels vitamin D, and lumbar and hip Z-scores in BMD at the time of the initial admission were recorded.

Results

The mean level of vitamin D was 13.4±7.5 ng/mL. In terms of serum levels of vitamin D, 28 patients (41.8%) had severe deficiency, 31 (46.3%) had insufficiency, and five patients (7.5%) had deficiency. Only three (4.5%) of the patients had sufficient levels of vitamin D. The hip Z-scores were significantly lower than lumbar Z scores. There was no significant difference in the lumbar and hip BMD measurements between the patients with and without steroid use. Lumbar Z-scores were significantly lower in non-ambulatory patients than ambulatory patients.

Conclusion

It is of utmost importance to evaluate the initial serum vitamin D levels in terms of bone health and prescribe replacement in case of deficiency/insufficiency in DMD patients. Since the decrease in the BMD is evident in this patient population, maintaining the mobilization as long as possible, providing loading on the bone for a long time, may be beneficial.

Fractures and bone health monitoring in boys with Duchenne muscular dystrophy managed within the Scottish Muscle Network

There are limited reports of radiologically confirmed fractures and bone health monitoring in with Duchenne muscular dystrophy. We performed a retrospective study of 91 boys, with a median age of 11.0 years, who are currently managed in Scotland with the aim to assess the frequency of radiologically confirmed fractures and report on bone health monitoring in relation to International Care Consensus Guidance. Of these boys, 59 (65%) were receiving glucocorticoid (GC) therapy and 23 (25%) had received previous treatment. Of those currently on GC, 37 (63%) had an assessment of bone mineral density and none had routine imaging for vertebral fractures during the study period. Of the 91 boys, 44 (48%) had sustained at least one symptomatic radiographically confirmed fracture. The probability of sustaining a first symptomatic fracture was 50% by 12.8 years old (95%CI: 12.1, 13.6). The most common sites for non-vertebral fracture were the femur and tibia. In this review of boys with DMD, almost half had sustained at least one radiologically confirmed symptomatic fracture. There is a need for standardized bone health monitoring in DMD that includes routine imaging of the spine to identify vertebral fractures, given the persistence of insult to the skeleton in these boys.

Insights into the pharmaceuticals and mechanisms of neurological orphan diseases: Current Status and future expectations

Several rare or orphan diseases have been characterized that singly affect low numbers of people, but cumulatively reach ∼6%-10% of the population in Europe and in the United States. Human genetics has shown to be broadly effective when evaluating subjacent genetic defects such as orphan genetic diseases, but on the other hand, a modest progress has been achieved toward comprehending the molecular pathologies and designing new therapies. Chemical genetics, placed at the interface of chemistry and genetics, could be employed to understand the molecular mechanisms of subjacent illnesses and for the discovery of new remediation processes. This review debates current progress in chemical genetics, and how a variety of compounds and reaction mechanisms can be used to study and ultimately treat rare genetic diseases. We focus here on a study involving Amyotrophic lateral sclerosis (ALS), Duchenne Muscular Dystrophy (DMD), Spinal muscular atrophy (SMA) and Familial Amyloid Polyneuropathy (FAP), approaching different treatment methods and the reaction mechanisms of several compounds, trying to elucidate new routes capable of assisting in the treatment profile.

Interventions to prevent and treat corticosteroid-induced osteoporosis and prevent osteoporotic fractures in Duchenne muscular dystrophy

BACKGROUND

Corticosteroid treatment is considered the 'gold standard' for Duchenne muscular dystrophy (DMD); however, it is also known to induce osteoporosis and thus increase the risk of vertebral fragility fractures. Good practice in the care of those with DMD requires prevention of these adverse effects. Treatments to increase bone mineral density include bisphosphonates and vitamin D and calcium supplements, and in adolescents with pubertal delay, testosterone. Bone health management is an important part of lifelong care for patients with DMD.

OBJECTIVES

To assess the effects of interventions to prevent or treat osteoporosis in children and adults with DMD taking long-term corticosteroids; to assess the effects of these interventions on the frequency of vertebral fragility fractures and long-bone fractures, and on quality of life; and to assess adverse events.

SEARCH METHODS

On 12 September 2016, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL Plus to identify potentially eligible trials. We also searched the Web of Science ISI Proceedings (2001 to September 2016) and three clinical trials registries to identify unpublished studies and ongoing trials. We contacted correspondence authors of the included studies in the review to obtain information on unpublished studies or work in progress.

SELECTION CRITERIA

We considered for inclusion in the review randomised controlled trials (RCTs) and quasi-RCTs involving any bone health intervention for corticosteroid-induced osteoporosis and fragility fractures in children, adolescents, and adults with a confirmed diagnosis of DMD. The interventions might have included oral and intravenous bisphosphonates, vitamin D supplements, calcium supplements, dietary calcium, testosterone, and weight-bearing activity.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports and selected potential studies for inclusion, following standard Cochrane methodology. We contacted study authors to obtain further information for clarification on published work, unpublished studies, and work in progress.

MAIN RESULTS

We identified 18 potential studies, of which two, currently reported only as abstracts, met the inclusion criteria for this review. Too little information was available for us to present full results or adequately assess risk of bias. The participants were children aged five to 15 years with DMD, ambulant and non-ambulant. The interventions were risedronate versus no treatment in one trial (13 participants) and whole-body vibration versus a placebo device in the second (21 participants). Both studies reported improved bone mineral density with the active treatments, with no improvement in the control groups, but the abstracts did not compare treatment and control conditions. All children tolerated whole-body vibration treatment. No study provided information on adverse events. Two studies are ongoing: one investigating whole-body vibration, the other investigating zoledronic acid.

AUTHORS' CONCLUSIONS

We know of no high-quality evidence from RCTs to guide use of treatments to prevent or treat corticosteroid-induced osteoporosis and reduce the risk of fragility fractures in children and adults with DMD; only limited results from two trials reported in abstracts were available. We await formal trial reports. Findings from two ongoing relevant studies and two trials, for which only abstracts are available, will be important in future updates of this review.

Body composition of patients with Duchenne muscular dystrophy: the Greek experience

Greece ranks among the first countries suffering from the obesity epidemic globally. The aim of the study was to evaluate body composition in Greek patients with Duchenne muscular dystrophy (DMD). We hypothesized that able-bodied patients would not differ from controls, in terms of adiposity, based on clinical observations during everyday practice.

STUDY DESIGN

Cross-sectional study of steroid-dependent DMD subjects, who underwent dual-energy X-ray absorptiometry and laboratory metabolic bone profile evaluation. Forty-two patients and thirty-one controls were studied. Overall, DMD subjects were shorter (height Z-score = -1.4, p = 0.01). Their bone mineral density (BMD) was low (lumbar spine BMD Z-score = -1.2, p < 0.01, subcranial total body BMD Z-score = -1.8, p < 0.01). Lean tissue mass (LTM) was also decreased (LTM Z-score = -2.2, p < 0.01). The above findings were more pronounced in adolescence. Regarding adiposity, increased fat mass (FM) was found only in pubertal DMD patients (FM Z-score = 1.4, p < 0.01), whereas prepubertal, able-bodied patients did not differ from controls, thus confirming the initial hypothesis. Finally, 65 % of DMD subjects had increased bone resorption markers and 57 % had suboptimal vitamin D levels. The importance of using native population as controls for body composition analysis is highlighted. In Greece, abnormal body composition in DMD patients is more striking when loss of ambulation occurs and not during the prepubertal period, due to the concurrent presence of obesity in the pediatric population. Thus, adolescents with this neuromuscular disorder should be targeted toward prompt lifestyle interventions.

Vitamin D in corticosteroid-naïve and corticosteroid-treated Duchenne muscular dystrophy: what dose achieves optimal 25(OH) vitamin D levels?

AIM

Assessment of the efficacy of vitamin D replenishment and maintenance doses required to attain optimal levels in boys with Duchenne muscular dystrophy (DMD).

METHOD

25(OH)-vitamin D levels and concurrent vitamin D dosage were collected from retrospective case-note review of boys with DMD at the Dubowitz Neuromuscular Centre. Vitamin D levels were stratified as deficient at <25 nmol/L, insufficient at 25-49 nmol/L, adequate at 50-75 nmol/L and optimal at >75 nmol/L.

RESULT

617 vitamin D samples were available from 197 boys (range 2-18 years)-69% from individuals on corticosteroids. Vitamin D-naïve boys (154 samples) showed deficiency in 28%, insufficiency in 42%, adequate levels in 24% and optimal levels in 6%. The vitamin D-supplemented group (463 samples) was tested while on different maintenance/replenishment doses. Three-month replenishment of daily 3000 IU (23 samples) or 6000 IU (37 samples) achieved optimal levels in 52% and 84%, respectively. 182 samples taken on 400 IU revealed deficiency in 19 (10%), insufficiency in 84 (47%), adequate levels in 67 (37%) and optimal levels in 11 (6%). 97 samples taken on 800 IU showed deficiency in 2 (2%), insufficiency in 17 (17%), adequate levels in 56 (58%) and optimal levels in 22 (23%). 81 samples were on 1000 IU and 14 samples on 1500 IU, with optimal levels in 35 (43%) and 9 (64%), respectively. No toxic level was seen (highest level 230 nmol/L).

CONCLUSIONS

The prevalence of vitamin D deficiency and insufficiency in DMD is high. A 2-month replenishment regimen of 6000 IU and maintenance regimen of 1000-1500 IU/day was associated with optimal vitamin D levels. These data have important implications for optimising vitamin D dosing in DMD.

Bone health measures in glucocorticoid-treated ambulatory boys with Duchenne muscular dystrophy

Osteoporosis is a major problem in boys with Duchenne Muscular Dystrophy (DMD), attributable to muscle weakness and glucocorticoid therapy. Consensus regarding bone health assessment and management is lacking. Lumbar spine areal bone mineral density (defined as bone mass per area of bone) by dual-energy X-ray absorptiometry (DXA) is frequently the primary measure used, but has limitations for boys with DMD. We retrospectively studied 292 ambulant glucocorticoid-treated boys with DMD categorized by functional mobility score, FMS 1, 2 or 3. We assessed DXA whole body and lumbar spine areal bone mineral density and content Z-scores adjusted for age and height, lateral distal femur areal bone mineral density Z-scores, frequency of fractures, and osteoporosis by International Society for Clinical Densitometry 2013 criteria. Whole body and femoral DXA indices decreased, while spine fractures increased, with declining motor function. Lumbar spine areal bone mineral density Z-scores appeared to improve with declining motor function. Bone mineral content Z-scores were consistently lower than corresponding bone mineral density Z-scores. Our findings highlight the complexity of assessing bone health in boys with DMD. Bone health indices worsened with declining motor function in ambulant boys, but interpretation was affected by measure and skeletal site examined. Whole body bone mineral content may be a valuable measure in boys with DMD. Lumbar spine areal bone mineral density Z-score as an isolated measure could be misleading. Comprehensive management of osteoporosis in boys with DMD should include vertebral fracture assessment.

Fracture in Duchenne Muscular Dystrophy: Natural History and Vitamin D Deficiency

The present study examined the natural history of fracture and vitamin D levels in Duchenne muscular dystrophy patients, who are vulnerable to osteoporosis and fractures. Retrospective analysis of a cohort of 48 Duchenne muscular dystrophy patients revealed that 43% of patients experienced ≥1 fracture. Fracture probabilities at ages 6, 9, 12, and 15 years were 4%, 9%, 31%, and 60% respectively, accelerating around the time of ambulation loss (mean age 11.8 ± 2.7 years). Chronic corticosteroid therapy was utilized in 69% of patients and was associated with all vertebral fractures. A history of vitamin D deficiency occurred in 84%, and 35% were currently deficient. Despite chronic vitamin D supplementation, 38% remained deficient. These results demonstrate that osteoporosis and fracture remain major concerns in Duchenne muscular dystrophy. Bone health should be optimized well before loss of ambulation, however current levels of vitamin D supplementation may be inadequate given high levels of deficiency.

Prophylactic oral bisphosphonate therapy in duchenne muscular dystrophy

INTRODUCTION

We assessed prophylactic use of bisphosphonate (BP) in Duchenne muscular dystrophy (DMD) patients on glucocorticoid (GC) therapy.

METHODS

Fifty-two DMD patients on daily GC were offered BP (oral risedronate). Patients were reviewed for tolerability, side effects, bone pain, and fracture frequency. Bone mineral density (BMD) was determined by annual dual energy X-ray absorptiometry. BP-treated patients were compared with 15 BP-naïve patients (untreated cohort).

RESULTS

Side effects occurred in 9 patients. Thirty-six patients continued BP therapy for over 12 months (mean, 3.6 years). Five treated patients reported bone pain. Three treated patients suffered a vertebral fracture, significantly less than in the untreated cohort (5/15). Lumbar spine adjusted BMD Z-scores remained unchanged in treated patients and were significantly greater than in the untreated cohort.

CONCLUSIONS

Prophylactic oral risedronate therapy was tolerated by most DMD patients. It appears to maintain BMD and may reduce fracture rate in DMD patients on GC. Muscle Nerve 54: 79-85, 2016.

Optimizing Bone Health in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder characterized by progressive muscle weakness, with eventual loss of ambulation and premature death. The approved therapy with corticosteroids improves muscle strength, prolongs ambulation, and maintains pulmonary function. However, the osteoporotic impact of chronic corticosteroid use further impairs the underlying reduced bone mass seen in DMD, leading to increased fragility fractures of long bones and vertebrae. These serious sequelae adversely affect quality of life and can impact survival. The current clinical issues relating to bone health and bone health screening methods in DMD are presented in this review. Diagnostic studies, including biochemical markers of bone turnover and bone mineral density by dual energy X-ray absorptiometry (DXA), as well as spinal imaging using densitometric lateral spinal imaging, and treatment to optimize bone health in patients with DMD are discussed. Treatment with bisphosphonates offers a method to increase bone mass in these children; oral and intravenous bisphosphonates have been used successfully although treatment is typically reserved for children with fractures and/or bone pain with low bone mass by DXA.

Corticosteroid Treatment Impact on Spinal Deformity in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is a progressive disease with loss of ambulation at around 9-10 years of age, followed, if untreated, by development of scoliosis, respiratory insufficiency, and death in the second decade of life. This review highlights the natural history of the disease, in particular, with regard to the development of the spinal deformity and how this complication has been modified by surgical interventions and overall by corticosteroid treatment. The beneficial effect of corticosteroids may have also an impact on the clinical trial design of the new emerging causative therapies.

Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy is one of the most severe muscle diseases to affect children. In the last twenty years, treatments have been established that have significantly improved patients' quality of life and life expectancy. The purpose of this article is to outline the main features of the disease and its treatment, and to examine possible future treatment options.

METHOD

The article is based on a literature search in PubMed, current international guidelines and our own clinical experience.

RESULTS

Close monitoring by an interdisciplinary rehabilitation team forms the basis of treatment. Treatment with glucocorticoids can slow disease progression and improve motor function in the short term. The treatment may cause side effects, which must be monitored and which may require intervention. A not insignificant proportion of patients have cognitive and neuropsychiatric problems that must be addressed. Active intervention in response to signs of respiratory or cardiac failure is important. More causal treatment of Duchenne muscular dystrophy is under testing and offers cautious hope for future patients.

INTERPRETATION

With improved treatment and increased life expectancy come new challenges for patients with Duchenne muscular dystrophy and their families, as well as new demands on the support services. This patient group requires close and comprehensive follow-up, also in the transition from child to adult.

Risk factors for osteoporosis, falls and fractures in hereditary myopathies and sporadic inclusion body myositis - A cross sectional survey

Background

The risk of osteoporosis is known in myopathies requiring long-term steroid treatment and Pompe disease, but not in other hereditary myopathies or sporadic inclusion body myositis (sIBM).

Methods

Risk factors of osteoporosis, laboratory parameters of bone metabolism, frequency of falls and fractures, walking ability, and pain were surveyed using questionnaires in 89 patients with sIBM and genetically confirmed myopathies facioscapulohumeral muscular dystrophy (FSHD), myotonic dystrophy types 1 and 2 (DM1, DM2), limb girdle muscular dystrophies (LGMD2A, LGMD2B, LGMD2I), MATR3 myopathy, and oculopharyngeal muscular dystrophy (OPMD). Additionally laboratory parameters of bone metabolism were determined.

Results

The mean age at examination per disease group ranged from 32 years in LGMD2A to 70 years in sIBM. Myopathies with a higher degree of walking impairment had a higher risk of falls (sIBM, LGMD2A, LGMD2B). At the time of examination 3.4% had a history of osteoporosis. The 25-OH D3 level was decreased in 20% of patients (and in 55% of patients with LGMDs), 57% of them were ambulatory. The 25-OH D3 level was significantly lower in patients with myopathies than in other neurological disorders (p < 0.001). 2.7 falls per year per person occurred. Fractures were reported in 6.8% of patients within the last year. They involved frequently the tibia bone. The pain score didn't correlate with either the walking disability (WGMS) score or the 25-OH D3 level.

Conclusion

The risk for osteoporosis and reduced 25-OH D3 level seems to be increased in wheelchair-bound patients with myopathy but also in patients with DM1 and autosomal-recessive myopathies.

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Risk factors for osteoporosis and fractures were analysed in hereditary myopathies.

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Wheelchair-bound patients - high risk for osteoporosis and fractures of tibia bone.

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Myopathy patients have lower vitamin D3 levels than controls.

Bone density and alendronate effects in Duchenne muscular dystrophy patients

INTRODUCTION

Patients with DMD have low bone mineral density (BMD) and are at high risk for fractures. We examined changes in BMD and the effects of alendronate in DMD patients treated at our institution in the last decade.

METHODS

Retrospective cohort study of 39 DMD patients.

RESULTS

Patients had screening dual energy x-ray absorptiometry (DXA) at an average age of 12 years. The vast majority had low Z-scores at the total hip and lumbar spine. Patients treated with glucocorticoids had a significantly lower Z-score at the spine than those not treated with glucocorticoids. Z-scores at the hip trended down without alendronate (P = 0.07) and trended up with alendronate (P = 0.4).

CONCLUSIONS

By age 12 years, most patients with DMD had low Z-scores. They may have benefitted from earlier screening. Z-score at the hip trended downward without alendronate and trended upward (stabilized) with alendronate, but these trends were not statistically significant.

Multidisciplinary approach to the management of myopathies

PURPOSE OF REVIEW

Aside from some inflammatory myopathies and very few genetic disorders, there are no therapies that make most patients with myopathies stronger. Consequently, the management of these patients can be frustrating for patients and their families as well as the clinicians taking care of them. Treatment of these patients must involve a comprehensive approach focused on limiting the secondary effects of skeletal muscle weakness, managing comorbidities associated with specific diseases, and, most importantly, optimizing patients' functional abilities and quality of life in terms of their ability to accomplish activities of daily living. While the approach to each patient differs depending on their disease, certain common themes can be addressed in each patient. This review highlights an approach centered on four conceptual themes ("the Four S's"): Strength therapies, Supportive care, Symptomatic therapies, and pSychological support.

RECENT FINDINGS

Although relatively few well-designed studies have been done that highlight conservative management of patients with various myopathies, an emerging literature helps guide the clinician in certain key areas, especially in relation to cardiac and pulmonary management of these patients.

SUMMARY

While disease-altering therapies have proven elusive for many muscle diseases, a multimodal approach to the conservative and supportive care of these patients can markedly improve their quality of life. Pharmacologic treatment options for specific myopathies will not be addressed in this article but are covered elsewhere in this issue of CONTINUUM.

Muscular dystrophy: new challenges and review of the current clinical trials

PURPOSE OF REVIEW

We provide a review of recent standards of care and therapeutic development in different forms of muscular dystrophies. This topic is relevant as the improved understanding of these disorders has not only led to a better definition of clinical course and to the development of standards of care for individual types of muscular dystrophies, but also culminated in different therapeutic approaches.

RECENT FINDINGS

Recent natural history studies have demonstrated the impact of new standards of care in different forms of muscular dystrophies, and identified areas of clinical management in which further developments are needed. The majority of the experimental studies are focused on Duchenne muscular dystrophy. Some of them target patients with specific mutations, such as antisense oligonucleotides, to induce exon skipping of specific mutations or drugs developed to allow read-through of nonsense mutations, whereas other therapies deal with secondary aspects of muscle degeneration, aiming, for example, at reducing inflammation or apoptosis, and may also be suitable for other forms of muscular dystrophies.

SUMMARY

The advances in the field of muscular dystrophy have resulted in improved clinical course and survival. The encouraging results of early experimental studies could further improve these outcomes in the future.

Muscular dystrophies

Muscular dystrophies are a heterogeneous group of inherited disorders that share similar clinical features and dystrophic changes on muscle biopsy. An improved understanding of their molecular bases has led to more accurate definitions of the clinical features associated with known subtypes. Knowledge of disease-specific complications, implementation of anticipatory care, and medical advances have changed the standard of care, with an overall improvement in the clinical course, survival, and quality of life of affected people. A better understanding of the mechanisms underlying the molecular pathogenesis of several disorders and the availability of preclinical models are leading to several new experimental approaches, some of which are already in clinical trials. In this Seminar, we provide a comprehensive review that integrates clinical manifestations, molecular pathogenesis, diagnostic strategy, and therapeutic developments.

Bone health and associated metabolic complications in neuromuscular diseases

This article reviews the recent literature regarding bone health as it relates to the patient living with neuromuscular disease (NMD). Studies defining the scope of bone-related disease in NMD are scant. The available evidence is discussed, focusing on abnormal calcium metabolism, increased fracture risk, and the prevalence of both scoliosis and hypovitaminosis D in Duchenne muscular dystrophy, amyotrophic lateral sclerosis, and spinal muscular atrophy. Future directions are discussed, including the urgent need for studies both to determine the nature and extent of poor bone health, and to evaluate the therapeutic effect of available osteoporosis treatments in patients with NMD.

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.

Insights into bone health in Duchenne muscular dystrophy

Poor bone health is a significant problem for patients with Duchenne muscular dystrophy (DMD), a progressive, disabling disease. Although the primary focus of DMD disease pathogenesis is degeneration of striated muscle, impairment of bone health likely has a role in the disease that has only been superficially examined to date. Deficiency of bone mineral density and increased incidence of bone fractures are well-recognized clinical components of the DMD phenotype. Furthermore, therapy with corticosteroids, an approved treatment for DMD that prolongs ambulation, may have multiple effects on bone health in DMD patients. This review examines the evidence in preclinical models and in human DMD disease that provides insight into the role performed by bone in the disease pathogenesis and phenotype of DMD. The information reviewed here points toward the need for mechanistic and therapeutic studies to optimize bone health in DMD patients.