The presence of non-progressive cognitive impairment is recognized as a common feature in a substantial proportion of patients with Duchenne muscular dystrophy (DMD). Concurrently, the amyloid beta peptide (Aβ42) protein has been associated with changes in memory and cognitive functions. Also, it has been shown that different subtypes of neural stem/progenitor cells (CD 34, CD 45, nestin) are involved in the innate repair of plasticity mechanisms by the injured brain, in which Nerve Growth Factor (NGF) acts as chemotactic agents to recruit such cells. Accordingly, the present study investigated levels of CD 34, CD 45, nestin and NGF in an attempt to investigate makers of neural regeneration in DMD. Neural damage was assayed in terms of Aβ42. Results showed that Aβ42 (21.9 ± 6.7 vs. 12.13 ± 4.5) was significantly increased among DMD patients compared to controls. NGF (165.8 ± 72 vs. 89.8 ± 35.9) and mononuclear cells expressing nestin (18.9 ± 6 vs. 9 ± 4), CD 45 (64 ± 5.4 vs. 53.3 ± 5.2) and CD34 (75 ± 6.2 vs. 60 ± 4.8) were significantly increased among DMD patients compared to controls. In conclusion cognitive function decline in DMD patients is associated with increased levels of Aβ42, which is suggested to be the cause of brain damage in such patients. The significant increase plasma NFG and in the number of mononuclear cells bearing CD34, CD45 and nestin indicates that regeneration is an ongoing process in these patients. However, this regeneration cannot counterbalance the damage induced by dystrophine mutation and increased Aβ42.
Duchenne muscular dystrophy; neural damage; cognitive
Limb-girdle muscular dystrophies (LGMD) are a highly heterogeneous group of muscle disorders, which first affect the voluntary muscles of the hip and shoulder areas. The definition is highly descriptive and less ambiguous by exclusion: non-Xlinked, non-FSH, non-myotonic, non-distal, nonsyndromic, and non-congenital. At present, the genetic classification is becoming too complex, since the acronym LGMD has also been used for a number of other myopathic disorders with overlapping phenotypes. Today, the list of genes to be screened is too large for the gene-by-gene approach and it is well suited for targeted next generation sequencing (NGS) panels that should include any gene that has been so far associated with a clinical picture of LGMD. The present review has the aim of recapitulating the genetic basis of LGMD ordering and of proposing a nomenclature for the orphan forms. This is useful given the pace of new discoveries. Thity-one loci have been identified so far, eight autosomal dominant and 23 autosomal recessive. The dominant forms (LGMD1) are: LGMD1A (myotilin), LGMD1B (lamin A/C), LGMD1C (caveolin 3), LGMD1D (DNAJB6), LGMD1E (desmin), LGMD1F (transportin 3), LGMD1G (HNRPDL), LGMD1H (chr. 3). The autosomal recessive forms (LGMD2) are: LGMD2A (calpain 3), LGMD2B (dysferlin), LGMD2C (γ sarcoglycan), LGMD2D (α sarcoglycan), LGMD2E (β sarcoglycan), LGMD2F (δ sarcoglycan), LGMD2G (telethonin), LGMD2H (TRIM32), LGMD2I (FKRP), LGMD2J (titin), LGMD2K (POMT1), LGMD2L (anoctamin 5), LGMD2M (fukutin), LGMD2N (POMT2), LGMD2O (POMTnG1), LGMD2P (dystroglycan), LGMD2Q (plectin), LGMD2R (desmin), LGMD2S (TRAPPC11), LGMD2T (GMPPB), LGMD2U (ISPD), LGMD2V (Glucosidase, alpha ), LGMD2W (PINCH2).
Limb-girdle muscular dystrophies; LGMD; NGS
We studied the consequences of the Nav1.4 mutation R1448H that is situated in the fourth voltage sensor of the channel and causes paramyotonia, a cold-induced myotonia followed by weakness. Previous work showed that the mutation uncouples inactivation from activation. We measured whole-cell Na+ currents at 10, 15, 20, and 25°C using HEK293 cells stably transfected with wildtype (WT) and R1448H Na+ channels. A Markov model was developed the parameters of which reproduced the data measured on WT and R1448H channels in the whole voltage and temperature range. It required an additional transient inactivated state and an additional closed-state inactivation transition not previously described. The model was used to predict single-channel properties, free energy barriers and temperature dependence of rates. It allowed us to draw the following conclusions: i) open-state inactivation results from a two-step process; ii) the channel re-openings that cause paramyotonia originate from enhanced deactivation/reactivation and not from destabilized inactivation; iii) the closed-state inactivation of R1448H is strikingly enhanced. We assume that latter explains the episodic weakness following cold-induced myotonia.
Paramyotonia; markov model; sodium channel; closed-state inactivation; channelopathy; skeletal muscle
This article shortly examines the biography, scientific activity and scientific work on neuromuscular diseases of the famous Russian neurologist Vladimir Roth who was the founder of neuromuscular disorders study in Russia. In 1876 he was the first in Russia who performed an autopsy and a detailed histological study of a case of progressive muscular atrophy, in which he did not find changes in the nervous system. He called this disease "muscular tabes" i.e. myopathy. In 1884 Vladimir Roth expressed his opinion about the nosological place of the peripheral type of muscular tabes to be considered as a distal myopathy. Dr. Roth became well-known for his monograph of the neuromuscular diseases, published in Moscow in 1895 under the name "Muscular Tabes" in which he described the history of neuromuscular diseases in a very detailed way, analyzing 1014 cases published in the world literature from 1830 to 1893 and 125 personal observations in the period 1874-1894. He performed a thorough analysis of the pattern of muscle involvement using both electrodiagnostic and histological study of muscles and central/peripheral nervous system. We report a short review of this monograph and two cases of peripheral (distal) myopathy.
Muscular tabes; distal myopathy; peripheral neuromuscular involvement
Recessive mutations in the ANO5 gene, encoding anoctamin 5, cause proximal limb girdle muscular dystrophy (LGMD2L), Miyoshi-type distal myopathy (MM3) and asymptomatic hyper- CKemia.
We report a woman with exertion-induced myalgia and weakness in the hip girdle manifesting at the age of 40. Creatine kinase (CK) was increased 20-fold. Histologically the dominating feature was necrotizing myopathy, but long-term immunosuppressive therapy did not change CK level or myopathic symptoms. Molecular genetic investigation led to the finding of the homozygous ANO5 c.191dupA mutation. This is a report of a muscular dystrophy due to ANO5 mutation presenting histologically as necrotizing myopathy. For this reason our finding extends the histological spectrum of myopathies due to ANO5 mutations as well as the possible differential diagnoses for necrotizing myopathy.
Anoctamin 5; limb girdle muscular dystrophy 2L; necrotizing myopathy
Charcot-Marie-Tooth type 2A disease (CMT2A) caused by mutations in the Mitofusin 2 gene (Mfn2) has been shown to be an early-onset axonal neuropathy with severe clinical course in the majority of the patients. In this study we present a unique phenotype of CMT2A disease characterized by late-onset polyneuropathy with a very mild clinical course. This rare form of CMT2A disease is caused by a new splice-site (c.311+1G>T) mutation within the MFN2 gene. Due to disturbance of the MFN2 splicing process, this mutation generates a short transcript which encodes a very short fragment of MFN2 protein. The c.311+1G>T mutation within the MFN2 gene results in the late -onset CMT2 disease.
Charcot-Marie-Tooth disease; late-onset polyneuropathy; Mitofusin 2; splice-site mutation
Because I am a neuromyologist that has dealt for many years with muscle hypertonia, I decided to write my memories in order to motivate younger researchers to try to duplicate the same observations and experiences.
We defined a whole range of conditions and symptoms, partly or in full. That is the first crucial step on the way to suppressing or relieving suffering. In some cases there was nothing we could do. In the other cases, we managed to diminish the uncomfortable symptoms. In still other cases, we cured the diseases, at least for a while. My conclusion is that great and systematic effort is always worth the trial. Maybe someone will follow us?!
Always again, I used to repeat to myself and to the others that, when approaching the patient, always the following rules should be respected: watch, listen and use your own common sense to evaluate what you observe; analyse why the symptoms occur in a concrete case; include the therapy in the logic of symptom development; continue to follow the patient and ask questions of yourself and of your colleagues; consult the literature; find the differences; ask again and again what else could be done ... and the solutions will appear unexpectedly.
Spasticity; cramps; neuromyotony
It is not known whether eosinophilic myositis is a specific histopathological feature of limb girdle muscular dystrophy 2A (LGMD2A).
Number and location of eosinophils in skeletal muscle biopsies (n=100) was analysed by Giemsa and modified hematoxylin/eosin staining in patients with genetically confirmed myopathies (LGMD2A, LGMD2B, LGMD2L, facioscapulohumeral muscular dystrophy, dystrophinopathy), histologically confirmed idiopathic inflammatory myopathies (sporadic inclusion body myositis (sIBM), dermatomyositis (DM), polymyositis), amyotrophic lateral sclerosis (neurogenic control), and normal controls.
The number of eosinophils/mm2 was significantly higher in LGMD2A, PM, DM, and sIBM compared to controls but not significantly higher than other myopathies. A large overlap in the number of eosinophils/mm2 between all groups was seen. In all disease groups eosinophils were mainly found endomysially (46- 88%) and intra- and perivascularly (4-37%). There was no correlation between the numbers of eosinophils/mm2 and (i) age at biopsy and (ii) the duration of the disease. The extent of myopathic, fibrotic, and inflammatory changes did not differ in samples with high and low eosinophil count.
Eosinophils seem to represent an unspecific histological finding in hereditary and inflammatory myopathies, but also amyotrophic lateral sclerosis.
Eosinophil; inflammatory myopathy; hereditary myopathy; limb girdle muscular dystrophy; calpainopathy; Giemsa staining; amyotrophic lateral sclerosis
Myotonic dystrophy (DM) is the most common adult muscular dystrophy, characterized by autosomal dominant progressive myopathy, myotonia and multiorgan involvement. To date two distinct forms caused by similar mutations have been identified. Myotonic dystrophy type 1 (DM1, Steinert's disease) was described more than 100 years ago and is caused by a (CTG)n expansion in DMPK, while myotonic dystrophy type 2 (DM2) was identified only 18 years ago and is caused by a (CCTG)n expansion in ZNF9/CNBP. When transcribed into CUG/CCUG-containing RNA, mutant transcripts aggregate as nuclear foci that sequester RNA-binding proteins, resulting in spliceopathy of downstream effector genes. Despite clinical and genetic similarities, DM1 and DM2 are distinct disorders requiring different diagnostic and management strategies. DM1 may present in four different forms: congenital, early childhood, adult onset and late-onset oligosymptomatic DM1. Congenital DM1 is the most severe form of DM characterized by extreme muscle weakness and mental retardation. In DM2 the clinical phenotype is extremely variable and there are no distinct clinical subgroups. Congenital and childhood-onset forms are not present in DM2 and, in contrast to DM1, myotonia may be absent even on EMG. Due to the lack of awareness of the disease among clinicians, DM2 remains largely underdiagnosed. The delay in receiving the correct diagnosis after onset of first symptoms is very long in DM: on average more than 5 years for DM1 and more than 14 years for DM2 patients. The long delay in the diagnosis of DM causes unnecessary problems for the patients to manage their lives and anguish with uncertainty of prognosis and treatment.
Myotonic dystrophy type 1 (Dm1); myotonic dystrophy type 2 (Dm2); management
The Mediterranean countries are distinguished with their peculiar genetic pool and diversities. Recessive diseases often present with their own founder mutations. In some instances this is shared with neighboring populations. Dominant disorders in the area are increasingly recognized as health care providing systems and technology improve. Among muscular dystrophies Duchenne and Becker types constitute the major fraction in almost all societies. This is followed by various forms of limb-girdle muscular dystrophy. Congenital dystrophies and other related rare types are a matter of recognition. The identification and registry of facio-scapulo-humeral and myotonic dystrophies vary in different states.
Frequency; incidence; muscular dystrophies; Mediterranean area
The role that atrial pacing therapy plays on the atrial fibrillation (AF) burden is still unclear. Aim of the study was to evaluate the effect of the atrial preference pacing algorithm on AF burden in patients affected by Myotonic Dystrophy type 1 (DM1) followed for a long follow up period. Sixty DM1 patients were -implanted with a dual chamber pacemaker (PM) for first degree or symptomatic type 1/type 2 second degree atrio-ventricular blocks- were followed for 2-years after implantation, by periodical examination. After 1 month of stabilization, they were randomized into two groups: 1) Patients implanted with conventional dual-chamber pacing mode (DDDR group) and 2) Patients implanted with DDDR plus Atrial Preference Pacing (APP) algorithm (APP ON group).
The results showed that atrial tachycardia (AT)/AF burden was significantly reduced at 1 year follow up in the APP ON group (2122 ± 428 minutes vs 4127 ± 388 minutes, P = 0.03), with a further reduction at the end of the 2 year follow up period (4652 ± 348 minutes vs 7564 ± 638 minutes, P = 0.005).
The data here reported show that the APP is an efficient algorithm to reduce AT/AF burden in DM1 patients implanted with dual chamber pacemaker.
Atrial overdrive algorithm; atrial preference pacing; supraventricular tachyarrhythmias; Myotonic Dystrophy type 1
The adult-onset form of Pompe disease had a wide clinical spectrum, ranging from asymptomatic patients with increased CK to muscle cramps and pain syndrome or rigid-spine syndrome. In addition clinical severity and disease progression are greatly variable. We report on a family with 3 siblings characterized by an unusual adult-onset Pompe disease including dysphagia and weakness of tongue, axial and limb-girdle muscles, in association with atypical globular inclusions in muscle fibres. Our study confirms the great clinical and histological variability of adult-onset Pompe disease and further supports the need of careful evaluation of bulbar function in patients affected by this pathology.
Pompe disease; globular inclusions; bulbar symptoms
Patients with muscle pathology are a challenge for anaesthesiologists because of possible life-threatening general anaesthesia complications. A review of the current medical literature on the issue clearly indicates that increasing awareness by anaesthesiologists in recent years has led to a reduction in the occurrence of adverse events in patients with diagnostically well-defined muscle disease. On the other hand, the current emerging aspect is that the great majority of complications concern subjects with clinically non-overt (silent to mildly symptomatic) and thus undiagnosed myopathy. With a view to improving prevention of possible critical anaesthesia complications in such patients, we present a "Safe Anaesthesia Table", listing both the anaesthetic drugs to be avoided and those considered harmless for myopathic patients, irrespective of age and type of pathology. In addition, a brief outline about the clinical aspects suggestive of a possible muscle pathology is also provided. Using "safe drugs" during routine surgical procedures in subjects with suspected undiagnosed myopathy will enable the anaesthesiologist to avoid delaying surgery, while protecting them from anaesthesia complications. By following this approach the presumed myopathy can be properly investigated after surgery.
anaesthesia complications; undiagnosed myopathy; safe anaesthesia; hyperCKemia
Glycogen-storage disease type II, also named Pompe disease, is caused by the deficiency of the enzyme acid alpha-glucosidase, which originates lysosomal glycogen accumulation leading to progressive neuromuscular damage. Early-onset Pompe disease shows a debilitating and frequently fulminating course. To date, more than 300 mutations have been described; the majority of them are unique to each affected individual. Most early-onset phenotypes are associated with frameshift mutations leading to a truncated alpha-glucosidase protein with loss of function. Founder effects are responsible from many cases from few highprevalence world regions. Herein we described two apparently unrelated cases affected with classical early-onset Pompe disease, both pertaining to a small region from Central Mexico (the State of San Luis Potosí), the same novel homozygous frameshift mutation at gene GAA (c.1987delC) was demonstrated in both cases. This GAA gene deletion implies a change of glutamine to serine at codon 663, and a new reading frame that ends after 33 base pairs, which leads to the translation of a truncated protein. This report contributes to widen the knowledge on the effect of pathogenic mutations in Pompe disease. Here we postulate the existence of a founder effect.
Early-onset Pompe disease; Acid maltase deficiency; Founder effect
The accessory deep peroneal (ADPN) nerve has been regarded as an anomalous nerve derived from the superficial peroneal nerve or its branch and supplies motor innervations for extensor digitorum brevis (EDB) and sensory innervations for the lateral part of the ankle and foot regions. The EDB is usually innervated exclusively by the deep peroneal nerve, a major branch of the the common peroneal nerve, however, in as many as 28% of patients (with same male/female frequency), one or both of the EDB muscles are (partially or exclusively) innervated by the ADPN nerve. This anomaly appears to be inherited in autosomal dominant fashion with incomplete gene penetrance. ADPN existence is of great clinical and surgical importance, and the aim of this study is to describe a very rare case of coexistence ADPN and anterior tarsal tunnel syndrome.
accessory deep peroneal nerve; anterior tarsal tunnel
Myotonic dystrophy type 1 (DM1) is the most common form of muscular dystrophy in adults. It affects many organs and systems besides muscle. Aim of this study was to assess frequency of erectile dysfunction (ED) and hypogonadism, the correlation between them and the impact of ED on quality of life (QoL) in patients with DM1. A series of 25 men (aged from 22 to 58 years) with a diagnosis of DM1 was analyzed. Muscular Impairment Rating Scale (MIRS) was used to assess severity of muscular involvement. Erectile function was assessed using the short form of the International Index of Erectile Function test (IIEF-5). Levels of follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone were assessed. All patients completed the Serbian version of the SF-36 questionnaire as a measure of health-related QoL. ED was present in 18 (72%) of patients. Seven (28%) patients were euogonadic, 16 (64%) had compensated hypogonadism and 2 (8%) had primary hypogonadism. ED was somewhat more common in patients with hypogonadism (78% vs. 57%). Mental composite score of SF-36 was lower in patients with ED (p<0.05). Our results showed that 72% of men with DM1 had ED and hypogonadism. Studies with larger number of subjects are needed to resolve cascade of events that lays behind ED in DM1. Development of therapeutic strategies may have positive impact on QoL. Substitutive therapy with androgens may be benefitial.
myotonic dystrophy type 1; erectile dysfunction; hypogonadis
Glycogen storage disease type II - also called Pompe disease or acid maltase deficiency - is an autosomal recessive metabolic disorder, caused by an accumulation of glycogen in the lysosome due to deficiency of the lysosomal acid alpha-glucosidase enzyme. Pompe disease is transmitted as an autosomal recessive trait and is caused by mutations in the gene encoding the acid α-glucosidase (GAA), located on chromosome 17q25.2-q25.3. The different disease phenotypes are related to the levels of residual GAA activity in muscles. The clinical spectrum ranging from the classical form with early onset and severe phenotype to not-classical form with later onset and milder phenotype is described.
Glycogen storage disease type II; Pompe disease; GAA activity
Glycogenosis II (GSD II) is an autosomal recessive lysosomal storage disorder resulting from acid alpha-glucosidase deficiency, subsequent accumulation of glycogen in tissues, impairment of autophagic processes and progressive cardiac, motor and respiratory failure.
The late-onset form is characterized by wide variability in residual enzyme activity, age of onset, rate of disease progression and phenotypical spectrum. Although the pathological process mainly affects the skeletal muscle, several other tissues may be involved in the course of the disease; therefore GSD II should be regarded as a multisystem disorder in which glycogen accumulation is present in skeletal and smooth muscle, heart, brain, liver, spleen, salivary glands, kidney and blood vessels.
In this review, we briefly summarize the main non-muscle targets of the pathological process in late-onset GSD II.
Further studies aimed at evaluating the extra-muscle involvement in this group of patients will help to better define clinical features and prognostic factors and to delineate the natural history of the disease.
Glycogenosis II; GSDII; Pompe disease
Mutations on the LMNA gene are responsible for an heterogeneous group of diseases. Overlapping syndromes related to LMNA gene alterations have been extensively reported. Study scope is to perform a systematic analysis of the overlapping syndromes so far described and to try to correlate the clinical features to the associated genetic alterations. We evaluated all the dominant overlapping syndromes reported by means of a PubMed search and by the analysis of the main databases containing the pathogenic LMNA gene variations and the associated diseases.
Metabolic alterations in association to skeletal and/or cardiac alterations proved to be the most frequent overlap syndrome. Overlapping syndromes are mostly associated to inframe mutations in exons 1, 2, 8 and 9. These data further improve the understanding of the pathogenesis of laminopathies.
Lamin A/C; laminopathies; LMNA overlapping syndromes
A 24-year-old female with 5 year history of heroin abuse experienced painless stiffness of elbow joints and weakness of shoulder and upper limb muscles. She was injecting herself 4-6 times daily alternatively in the upper extremities, sparing the lower limbs. Electromyography (EMG) showed myopathic changes in clinically affected and unaffected muscles. Magnetic resonance imaging (MRI) revealed muscle fibrosis in directly injected muscles, whereas in subcutaneous fat and within muscles of anterior and posterior compartments of both thighs, not directly injected, there were signal changes supportive of oedema and inflammation. EMG and MRI were congruent in showing abnormalities in muscles not directly injected, suggesting long distant effects of heroin or adulterants with a mechanism either toxic or immunologically mediated.
Heroin myopathy; focal myopathy; muscle fibrosis
Lamins (LMNA) are the main proteins of the nuclear lamina considered to be the ancestors of all intermediate filament proteins. They form complex protein assemblies with integral proteins of the inner nuclear membrane, transcriptional regulators, histones and chromatin modifiers. During recent years, interest in lamins has greatly increased due to the identification of many distinct heritable human disorders associated with lamin mutations. These disorders, collectively termed laminopathies, range from muscular dystrophies to premature aging. They may affect muscle, fat, bone, nerve and skin tissues. The workshop was addressed to understand lamin organization and its roles in nuclear processes, mutations in lamins affecting cell and tissues functions, the biology of the nucleus and laminopathic disease mechanisms, all aspects important for designing future therapies.
LMNA A/C gene; laminopathies; Emery-Dreifuss muscular dystrophy