Exome Sequencing Identifies DYNC1H1 Variant Associated With Vertebral Abnormality and Spinal Muscular Atrophy With Lower Extremity Predominance
2015; 52 (2): 239-244
COOPERATIVE INTERNATIONAL NEUROMUSCULAR RESEARCH GROUP DUCHENNE NATURAL HISTORY STUDY DEMONSTRATES INSUFFICIENT DIAGNOSIS AND TREATMENT OF CARDIOMYOPATHY IN DUCHENNE MUSCULAR DYSTROPHY
MUSCLE & NERVE
2014; 50 (2): 250-256
Molecular diagnosis of the distal spinal muscular atrophies or distal hereditary motor neuropathies remains challenging because of clinical and genetic heterogeneity. Next generation sequencing offers potential for identifying de novo mutations of causative genes in isolated cases.We present a 3.6-year-old girl with congenital scoliosis, equinovarus, and L5/S1 left hemivertebra who demonstrated delayed walking and lower extremities atrophy. She was negative for SMN1 deletion testing, and parents show no sign of disease.Whole exome sequencing of the affected girl showed a novel de novo heterozygous missense mutation c.1792C>T (p.Arg598Cys) in the tail domain of the DYNC1H1 gene encoding for cytoplasmic dynein heavy chain 1. The mutation changed a highly conserved amino acid and was absent from both parents.De novo mutations of DYNC1H1 have been found in individuals with autosomal dominant mental retardation with neuronal migration defects. Dominantly inherited mutations of DYNC1H1 have been reported to cause spinal muscular atrophy with predominance of lower extremity involvement and Charcot-Marie-Tooth type 2O. This is the first report of a de novoDYNC1H1 mutation associated with the spinal muscular atrophy with predominance of lower extremity phenotype with a spinal deformity (lumbar hemivertebrae). This case also demonstrates the power of next generation sequencing to discover de novo mutations on a genome-wide scale.
View details for DOI 10.1016/j.pediatrneurol.2014.09.003
View details for Web of Science ID 000349580600019
View details for PubMedID 25484024
Novel large deletion in the ACTA1 gene in a child with autosomal recessive nemaline myopathy
2014; 24 (4): 331-334
Cardiomyopathy is a common cause of morbidity and death in patients with Duchenne muscular dystrophy (DMD).This investigation was a cross-sectional cross-sectional analysis of clinical data from the multi-institutional Cooperative International Neuromuscular Research Group (CINRG) DMD Natural History Study of 340 DMD patients aged 2-28 years. Cardiomyopathy was defined as shortening fraction (SF) <28% or ejection fraction (EF) <55%.Two hundred thirty-one participants reported a prior clinical echocardiogram study, and 174 had data for SF or EF. The prevalence of cardiomyopathy was 27% (47 of 174), and it was associated significantly with age and clinical stage. The association of cardiomyopathy with age and clinical stage was not changed by glucocorticoid use as a covariate (P > 0.68). In patients with cardiomyopathy, 57% (27 of 47) reported not taking any cardiac medications. Cardiac medications were used in 12% (15 of 127) of patients without cardiomyopathy.We found that echocardiograms were underutilized, and cardiomyopathy was undertreated in this DMD natural history cohort.
View details for DOI 10.1002/mus.24163
View details for Web of Science ID 000340237500014
View details for PubMedID 24395289
'Double trouble': diagnostic challenges in Duchenne muscular dystrophy in patients with an additional hereditary skeletal dysplasia.
2013; 23 (12): 955-961
Nemaline myopathy (NM) is a genetically and clinically heterogeneous disorder resulting from a disruption of the thin filament proteins of the striated muscle sarcomere. The disorder is typically characterized by muscle weakness including the face, neck, respiratory, and limb muscles and is clinically classified based on the age of onset and severity. Mutations in the ACTA1 gene contribute to a significant proportion of NM cases. The majority of ACTA1 gene mutations are missense mutations causing autosomal dominant NM by producing an abnormal protein. However, approximately 10% of ACTA1 gene mutations are associated with autosomal recessive NM; these mutations are associated with loss of protein function. We report the first case of a large deletion in the ACTA1 gene contributing to autosomal recessive NM. This case illustrates the importance of understanding disease mechanisms at the molecular level to accurately infer the inheritance pattern and potentially aid with clinical management.
View details for DOI 10.1016/j.nmd.2013.12.006
View details for Web of Science ID 000334135200005
View details for PubMedID 24447884
The cooperative international neuromuscular research group Duchenne natural history study: Glucocorticoid treatment preserves clinically meaningful functional milestones and reduces rate of disease progression as measured by manual muscle testing and other commonly used clinical trial outcome measures
MUSCLE & NERVE
2013; 48 (1): 55-67
Duchenne muscular dystrophy (DMD) is caused by mutations in Dystrophin and affects 1 in 3600-6000 males. It is characterized by progressive weakness leading to loss of ambulation, respiratory insufficiency, cardiomyopathy, and scoliosis. We describe the unusual phenotype of 3 patients with skeletal dysplasias in whom an additional diagnosis of DMD was later established. Two unrelated boys presented with osteogenesis imperfecta due to point mutations in COL1A1 and were both subsequently found to have a 1 bp frameshift deletion in the Dystrophin gene at age 3 and age 15 years, respectively. The third patient had a diagnosis of pseudoachondroplasia caused by a mutation in the COMP gene and was found to have a deletion of exons 48-50 in Dystrophin at age 9. We discuss the atypical presentation caused by the concomitant presence of 2 conditions affecting the musculoskeletal system, emphasizing aspects that may confound the presentation of a well-characterized disease like DMD. Additional series of patients with DMD and a secondary inherited condition are necessary to establish the natural history in this "double trouble" population. The recognition and accurate diagnosis of patients with two independent genetic disease processes is essential for management, prognosis, genetic risk assessment, and discussion regarding potential therapeutic interventions.
View details for DOI 10.1016/j.nmd.2013.08.003
View details for PubMedID 24070816
Pentoxifylline as a rescue treatment for DMD A randomized double-blind clinical trial
2012; 78 (12): 904-913
introduction: Glucocorticoid (GC) therapy in Duchenne muscular dystrophy (DMD) has altered disease progression, necessitating contemporary natural history studies.The Cooperative Neuromuscular Research Group (CINRG) DMD Natural History Study (DMD-NHS) enrolled 340 DMD males, ages 2-28 years. A comprehensive battery of measures was obtained.A novel composite functional "milestone" scale scale showed clinically meaningful mobility and upper limb abilities were significantly preserved in GC-treated adolescents/young adults. Manual muscle test (MMT)-based calculations of global strength showed that those patients <10 years of age treated with steroids declined by 0.4 ± 0.39 MMT unit/year, compared with -0.4 ± 0.39 MMT unit/year in historical steroid-naive subjects. Pulmonary function tests (PFTs) were relatively preserved in steroid-treated adolescents. The linearity and magnitude of decline in measures were affected by maturational changes and functional status.In DMD, long-term use of GCs showed reduced strength loss and preserved functional capabilities and PFTs compared with previous natural history studies performed prior to the widespread use of GC therapy.
View details for DOI 10.1002/mus.23808
View details for Web of Science ID 000320787700006
View details for PubMedID 23649481
LIQUID FORMULATION OF PENTOXIFYLLINE IS A POORLY TOLERATED TREATMENT FOR DUCHENNE DYSTROPHY
MUSCLE & NERVE
2011; 44 (2): 170-173
To determine whether pentoxifylline (PTX) slows the decline of muscle strength and function in ambulatory boys with Duchenne muscular dystrophy (DMD).This was a multicenter, randomized, double-blinded, controlled trial comparing 12 months of daily treatment with PTX or placebo in corticosteroid-treated boys with DMD using a slow-release PTX formulation (~20 mg/kg/day). The primary outcome was the change in mean total quantitative muscle testing (QMT) score. Secondary outcomes included changes in QMT subscales, manual muscle strength, pulmonary function, and timed function tests. Outcomes were compared using Student t tests and a linear mixed-effects model. Adverse events (AEs) were compared using the Fisher exact test.A total of 64 boys with DMD with a mean age of 9.9 ± 2.9 years were randomly assigned to PTX or placebo in 11 participating Cooperative International Neuromuscular Research Group centers. There was no significant difference between PTX and the placebo group in total QMT scores (p = 0.14) or in most of the secondary outcomes after a 12-month treatment. The use of PTX was associated with mild to moderate gastrointestinal or hematologic AEs.The addition of PTX to corticosteroid-treated boys with DMD at a moderate to late ambulatory stage of disease did not improve or halt the deterioration of muscle strength and function over a 12-month study period.This study provides Class I evidence that treatment with PTX does not prevent deterioration in muscle function or strength in corticosteroid-treated boys with DMD.
View details for Web of Science ID 000301937700014
View details for PubMedID 22402864
SPP1 genotype is a determinant of disease severity in Duchenne muscular dystrophy
2011; 76 (3): 219-226
In this study we performed an open-label, pilot study of an orally administered liquid formulation of immediate-release pentoxifylline (PTX) on patients with Duchenne muscular dystrophy (DMD). Treatment efficacy, safety, and tolerability were assessed.The tolerability and safety of PTX and measures of muscle strength and function were evaluated during 12 months of treatment.Seventeen boys with DMD, between 4 and 8 years of age, were enrolled at one of five Cooperative International Neuromuscular Research Group (CINRG) centers. Only 9 were able to complete the 12-month PTX treatment phase; the primary reason for discontinuation was adverse events. Intolerable gastrointestinal side effects were experienced by 65% of participants. Two participants had severe leukopenia that resolved with medication withdrawal.Open-label treatment with a liquid formulation of immediate-release PTX resulted in a high incidence of adverse events in boys with DMD. Poor tolerability of this PTX formulation precluded adequate assessment of efficacy.
View details for DOI 10.1002/mus.22127
View details for Web of Science ID 000293383700003
View details for PubMedID 21674534
Limb-Girdle and Congenital Muscular Dystrophies: Current Diagnostics, Management, and Emerging Technologies
CURRENT NEUROLOGY AND NEUROSCIENCE REPORTS
2010; 10 (4): 267-276
Duchenne muscular dystrophy (DMD) is the most common single-gene lethal disorder. Substantial patient-patient variability in disease onset and progression and response to glucocorticoids is seen, suggesting genetic or environmental modifiers.Two DMD cohorts were used as test and validation groups to define genetic modifiers: a Padova longitudinal cohort (n = 106) and the Cooperative International Neuromuscular Research Group (CINRG) cross-sectional natural history cohort (n = 156). Single nucleotide polymorphisms to be genotyped were selected from mRNA profiling in patients with severe vs mild DMD, and genome-wide association studies in metabolism and polymorphisms influencing muscle phenotypes in normal volunteers were studied.Effects on both disease progression and response to glucocorticoids were observed with polymorphism rs28357094 in the gene promoter of SPP1 (osteopontin). The G allele (dominant model; 35% of subjects) was associated with more rapid progression (Padova cohort log rank p = 0.003), and 12%-19% less grip strength (CINRG cohort p = 0.0003).Osteopontin genotype is a genetic modifier of disease severity in Duchenne dystrophy. Inclusion of genotype data as a covariate or in inclusion criteria in DMD clinical trials would reduce intersubject variance, and increase sensitivity of the trials, particularly in older subjects.
View details for Web of Science ID 000286371900007
View details for PubMedID 21178099
PPAR alpha L162V underlies variation in serum triglycerides and subcutaneous fat volume in young males
BMC MEDICAL GENETICS
The muscular dystrophies show muscle degeneration and regeneration (necrotizing myopathy) on muscle biopsy, typically associated with elevated serum creatine kinase, and muscle weakness. In 1986, the first causative gene was identified for the most prevalent and best-characterized form of muscular dystrophy, Duchenne muscular dystrophy. Over the past 25 years, the number of other genes determined to cause different subtypes has grown rapidly. This review gives a synopsis of the 45 genetically defined types of muscular dystrophies and describes the clinical, pathologic, and molecular aspects of each disease. DNA diagnosis remains the most sensitive and specific method for differential diagnosis, but molecular diagnostics can be expensive and complex (because of multiple genes at multiple testing facilities) and reimbursement may be challenging to obtain. However, emerging DNA sequencing technologies (eg, single-molecule third-generation sequencing units) promise to dramatically reduce the complexity and costs of DNA diagnostics. Treatment for nearly all forms remains supportive and is aimed at preventing complications. However, several promising approaches have entered clinical trials, providing tangible hope that quality of life will improve for many patients in the near future.
View details for DOI 10.1007/s11910-010-0119-1
View details for Web of Science ID 000278111800003
View details for PubMedID 20467841
CINRG randomized controlled trial of creatine and glutamine in Duchenne muscular dystrophy
ANNALS OF NEUROLOGY
2005; 58 (1): 151-155
Of the five sub-phenotypes defining metabolic syndrome, all are known to have strong genetic components (typically 50-80% of population variation). Studies defining genetic predispositions have typically focused on older populations with metabolic syndrome and/or type 2 diabetes. We hypothesized that the study of younger populations would mitigate many confounding variables, and allow us to better define genetic predisposition loci for metabolic syndrome.We studied 610 young adult volunteers (average age 24 yrs) for metabolic syndrome markers, and volumetric MRI of upper arm muscle, bone, and fat pre- and post-unilateral resistance training.We found the PPARalpha L162V polymorphism to be a strong determinant of serum triglyceride levels in young White males, where carriers of the V allele showed 78% increase in triglycerides relative to L homozygotes (LL = 116 +/- 11 mg/dL, LV = 208 +/- 30 mg/dL; p = 0.004). Men with the V allele showed lower HDL (LL = 42 +/- 1 mg/dL, LV = 34 +/- 2 mg/dL; p = 0.001), but women did not. Subcutaneous fat volume was higher in males carrying the V allele, however, exercise training increased fat volume of the untrained arm in V carriers, while LL genotypes significantly decreased in fat volume (LL = -1,707 +/- 21 mm3, LV = 17,617 +/- 58 mm3 ; p = 0.002), indicating a systemic effect of the V allele on adiposity after unilateral training. Our study suggests that the primary effect of PPARalpha L162V is on serum triglycerides, with downstream effects on adiposity and response to training.Our results on association of PPARalpha and triglycerides in males showed a much larger effect of the V allele than previously reported in older and less healthy populations. Specifically, we showed the V allele to increase triglycerides by 78% (p = 0.004), and this single polymorphism accounted for 3.8% of all variation in serum triglycerides in males (p = 0.0037).
View details for DOI 10.1186/1471-2350-8-55
View details for Web of Science ID 000250533300001
View details for PubMedID 17705849
Update on diagnosis and treatment of hereditary and acquired polyneuropathies in childhood.
Supplements to Clinical neurophysiology
2004; 57: 255-271
Drop episodes in Coffin-Lowry syndrome: an unusual type of startle response
2000; 2 (3): 173-176
We tested the efficacy and safety of glutamine (0.6 gm/kg/day) and creatine (5 gm/day) in 50 ambulant boys with Duchenne muscular dystrophy in a 6-month, double-blind, placebo-controlled clinical trial. Drug efficacy was tested by measuring muscle strength manually (34 muscle groups) and quantitatively (10 muscle groups). Timed functional tests, functional parameters, and pulmonary function tests were secondary outcome measures. Although there was no statistically significant effect of either therapy based on manual and quantitative measurements of muscle strength, a disease-modifying effect of creatine in older Duchenne muscular dystrophy and creatine and glutamine in younger Duchenne muscular dystrophy cannot be excluded. Creatine and glutamine were well tolerated.
View details for DOI 10.1002/ana.20523
View details for Web of Science ID 000230287900018
View details for PubMedID 15984021
We present a patient with a complete Coffin-Lowry syndrome, associated with drop episodes precipitated by sudden auditory stimuli, which provoked in turn, a definite loss of muscle tone in both legs. Electrophysiological studies showed that these episodes are an unusual type of startle response and that they may be associated with Coffin-Lowry syndrome.
View details for Web of Science ID 000089792500007
View details for PubMedID 11022143