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Introduction: Reported frequencies of cardiomyopathy in limb girdle muscular dystrophy R9 (LGMDR9) vary. We describe the frequency and age at onset of cardiomyopathy in an LDMDR9 cohort., Methods: Echocardiograms from 56 subjects (157 echocardiograms) with LGMDR9 were retrospectively reviewed. The cumulative probability of having an abnormal echocardiogram as a function of age was assessed by survival analysis for interval-censored data by genotype. Correlations between cardiac and clinical function were evaluated., Results: Twenty-five (45%) participants had cardiomyopathy. The median age at first abnormal echocardiogram for subjects homozygous for the c.826C>A variant was 54.2 y compared to 18.1 y for all other fukutin-related protein (FKRP) genotypes (P < .0001). There was a weak correlation between ejection fraction and 10-Meter Walk Test speed (r = 0.25), but no correlation with forced vital capacity (r = 0.08)., Discussion: Cardiomyopathy is prevalent among those with LGMDR9 and occurs later in subjects homozygous for the c.826C>A mutation. These data will help to guide surveillance and management., (© 2020 The Authors. Muscle & Nerve published by Wiley Periodicals LLC.)

Introduction: A calpain-3 (CAPN3) gene heterozygous deletion (c.643&#95;663del21) was recently linked to autosomal dominant (AD) limb-girdle muscular dystrophy. However, the possibility of digenic disease was raised. We describe 3 families with AD calpainopathy carrying this isolated mutation., Methods: Probands heterozygous for CAPN3 c.643&#95;663del21 were identified by targeted next generation or whole exome sequencing. Clinical findings were collected for probands and families. Calpain-3 muscle Western blots were performed in 3 unrelated individuals., Results: Probands reported variable weakness in their 40s or 50s, with myalgia, back pain, or hyperlordosis. Pelvic girdle muscles were affected with adductor and hamstring sparing. Creatine kinase was normal to 1,800 U/L, independent of weakness severity. Imaging demonstrated lumbar paraspinal muscle atrophy. Electromyographic findings and muscle biopsies were normal to mildly myopathic. Muscle calpain-3 expression was reduced., Discussion: This study provides further evidence for AD calpainopathy associated with CAPN3 c.643&#95;663del21. No pathogenic variants in other genes known to cause myopathy were detected. Muscle Nerve 57: 679-683, 2018., (© 2017 Wiley Periodicals, Inc.)

Introduction: McArdle disease is a glycogen storage disease caused by mutations in the PYGM gene encoding myophosphorylase. It manifests classically with childhood-onset exercise-induced pain., Methods: We report the characteristics of 2 unrelated patients with a new homozygous mutation of the PYGM gene., Results: Two patients, aged 76 and 79 years, presented with severe upper and lower limb atrophy and weakness. Additionally, 1 patient presented with bilateral ptosis, and the other with camptocormia. In both patients, symptoms had developed progressively in the 2 preceding years, and there was no history of exercise intolerance. Both patients demonstrated myogenic abnormalities on electromyography, multiple glycogen-containing vacuoles and undetectable muscle myophosphorylase activity on muscle biopsy, and a novel homozygous frameshift p.Lys42Profs*48 PYGM mutation., Conclusions: This report expands the phenotype and genotype of McArdle disease and suggests that PYGM mutations should be looked for in patients with very late-onset myopathy with no previous history of exercise intolerance. Muscle Nerve 57: 157-160, 2018., (© 2017 Wiley Periodicals, Inc.)

Introduction: Little is known about the frequency of cardiopulmonary failure in limb-girdle muscular dystrophy type 2A (calpainopathy) patients, although some studies have reported severe cardiomyopathy or respiratory failure., Methods: To clarify the frequency of cardiopulmonary dysfunction in this patient population, we retrospectively reviewed the respiratory and cardiac function of 43 patients with calpainopathy., Results: Nine of the 43 patients had forced vital capacity (FVC) < 80%, and 3 used noninvasive positive pressure ventilation. Mean FVC was significantly lower in patients who were nonambulant and had normal creatine kinase levels. Only 1 patient had a prolonged QRS complex duration. Echocardiography revealed that 1 patient had very mild left ventricular dysfunction., Conclusions: These findings suggest that patients with calpainopathy may develop severe respiratory failure, but cardiac dysfunction is infrequent. Muscle Nerve 55: 465-469, 2017., (© 2016 The Authors. Muscle & Nerve Published by Wiley Periodicals, Inc.)

Introduction: Limb girdle muscular dystrophies (LGMDs) are characterized by high molecular heterogeneity, clinical overlap, and a paucity of specific biomarkers. Their molecular definition is fundamental for prognostic and therapeutic purposes., Methods: We created an Italian LGMD registry that included 370 molecularly defined patients. We reviewed detailed retrospective and prospective data and compared each LGMD subtype for differential diagnosis purposes., Results: LGMD types 2A and 2B are the most frequent forms in Italy. The ages at disease onset, clinical progression, and cardiac and respiratory involvement can vary greatly between each LGMD subtype. In a set of extensively studied patients, targeted next-generation sequencing (NGS) identified mutations in 36.5% of cases., Conclusion: Detailed clinical characterization combined with muscle tissue analysis is fundamental to guide differential diagnosis and to address molecular tests. NGS is useful for diagnosing forms without specific biomarkers, although, at least in our study cohort, several LGMD disease mechanisms remain to be identified. Muscle Nerve 55: 55-68, 2017., (© 2016 Wiley Periodicals, Inc.)

Introduction: We retrospectively reviewed respiratory and cardiac function in patients with dysferlinopathy, including 2 autopsy cases with respiratory dysfunction., Methods: Subjects included 48 patients who underwent respiratory evaluation (n = 47), electrocardiography (n = 46), and echocardiography (n = 23)., Results: Of the 47 patients, 10 had reduced percent forced vital capacity (%FVC), and 4 required non-invasive positive pressure ventilation. %FVC was significantly correlated with disease duration, and mean %FVC was significantly lower in non-ambulatory patients, as well as in those aged ≥65 years with normal creatine kinase levels. On electrocardiography, QRS complex duration was prolonged in 19 patients, although no significant association with age, disease duration, or respiratory function was found. Echocardiography indicated no left ventricular dysfunction in any patient. Histopathology of autopsied cases revealed mild cardiomyopathy and moderate diaphragm involvement., Conclusion: Patients with dysferlinopathy may develop severe respiratory failure and latent cardiac dysfunction. Both respiratory and cardiac function should be monitored diligently., (© 2015 Wiley Periodicals, Inc.)

Introduction: Mutations in the anoctamin 5 gene (ANO5) have been recently identified.They cause limb girdle muscular dystrophy (LGMD2L) and Miyoshi muscular dystrophy., Methods: Clinical findings of four unrelated patients are reviewed. Mutation detection was performed by direct sequencing of the ANO5 exons., Results: We identified four novel mutations in the ANO5 gene. In one patient, a novel homozygous mutation (c.1965G>C). In three patients, the recurrent heterozygous exon 5 c.191dupA mutation is combined with other variants to form a compound heterozygous state: in two cases, novel splice site mutations in intron 5 (c.295-1G>A) and in intron 14 (c.1407+5G>A), and in one case, a novel missense mutation in exon 4 (c.172C>T)., Conclusions: The cases reported here should help to better understand the important role of mutation screening in the ANO5 gene in patients with adult onset muscular dystrophy and very high CK levels., (Copyright © 2012 Wiley Periodicals, Inc.)

Dysphagia has not been reported in genetically confirmed limb-girdle muscular dystrophy type 2B (LGMD2B). A 40-year-old woman reported exercise-induced calf pain at age 34, followed by progressive lower and upper limb weakness. At age 38, progressive dysphagia for solids, and subsequently liquids, ensued. Endoscopic and videofluoroscopic-radiological findings indicated a myopathic swallowing disorder. Molecular genetic analysis confirmed two dysferlin gene mutations consistent with a compound heterozygote state. Progressive dysphagia should be considered as part of the expanding dysferlinopathy phenotype., (Copyright © 2011 Wiley Periodicals, Inc.)

The diagnosis of late-onset (childhood and adult) Pompe disease can often be challenging, as it is a rare disease and the heterogeneous clinical presentation can mimic the presentation of other neuromuscular disorders. The objective was to develop a consensus-based algorithm for the diagnosis of late-onset Pompe disease. A systematic literature search was conducted, and an expert panel composed of neuromuscular specialists and individuals with expertise in Pompe disease reviewed the literature and convened for consensus development. An algorithm for the diagnosis of late-onset Pompe disease was created. Patients presenting with either a limb-girdle syndrome or dyspnea secondary to diaphragm weakness should undergo further testing, including evaluations of muscle strength, motor function, and pulmonary function. A blood-based acid alpha-glucosidase (GAA) enzyme activity assay is the recommended tool to screen for GAA enzyme deficiency. The diagnosis should be confirmed by a second test: either a second GAA enzyme activity assay in another tissue or GAA gene sequencing.

We describe a 10-year-old girl with limb-girdle muscular dystrophy type 2C (LGMD2C, gamma-sarcoglycan deficiency) with additional features that include progressive lower limb spasticity, peripheral neuropathy, and ataxia. The gene for LGMD2C lies in close approximation to the gene for autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) on chromosome 13q12. The clinical presentation was suspicious for a genomic rearrangement affecting the expression of both genes. Using chromosomal microarray analysis, a homozygous deletion that encompassed the genes for both disorders was identified. This is the first report of a patient with both neurological diseases, and this case illustrates the clinical utility of microarray technology in the investigation of patients with unusual presentations.

In this review, we draw attention to the multiple mechanisms responsible for the pathogenesis of cardiomyopathies in patients with muscular dystrophies. More than one single mechanism is likely to be involved in the development of skeletal and cardiac muscle pathology even when there is a single protein defect. The best example is dystrophin deficiency, in which increased sarcolemmal permeability following eccentric exercise, reduced force generation, and abnormal signaling are all likely to contribute to the progressive muscle damage observed. In other conditions, such as the sarcoglycanopathies, a protein deficiency both in the striated cardiomyocte and the vascular smooth muscle appears to play a significant role. An entirely different mechanism of disease is likely in defects of nuclear envelope proteins, although the precise pathogenesis of this group of conditions is still not clear. Differences between the organization of skeletal and cardiac muscle protein complex are also only starting to emerge and will very likely be the focus of future research.

We report a family with markedly variable myopathic weakness due to facioscapulohumeral muscular dystrophy (FSHD). The proband developed mild late-onset proximal limb weakness. Her two daughters had severe infantile facial diplegia, initially diagnosed as Möbius syndrome, and mild childhood-onset limb weakness and scapular winging. Results of facial muscle electromyography and muscle histopathology supported a myopathic disorder. This case study further highlights the broad clinical spectrum and intrafamily variability in FSHD, and the occasional absence of a positive correlation between fragment size and disease onset. Moreover, this study underscores the importance of considering FSHD in cases of infantile facial diplegia, especially in patients not demonstrating the full clinical features of Möbius syndrome. In difficult cases, facial muscle electromyography may help to differentiate myopathic from neuropathic weakness, and help guide further diagnostic studies.