Epidemiology of seropositive myasthenia gravis in Sardinia: A population-based study in the district of Sassari.

INTRODUCTION/AIMS: The global incidence and prevalence of myasthenia gravis (MG) range between 6-31/million and 10-37/100,000, respectively. Sardinia is a high-risk region for different immune-mediated disorders, but the epidemiology of MG remains unclear. We determined the epidemiology of MG with acetylcholine receptor (AChR)-immunoglobulin G (IgG) and muscle-specific tyrosine kinase (MuSK)-IgG in the district of Sassari (North-Western Sardinia; population, 325,288). METHODS: From the laboratory of the University Hospital of Sassari (reference for AChR/MuSK-IgG testing in Sardinia since 1998) and the main neurology units in Sardinia, we retrospectively identified MG patients with (1) AChR-IgG and/or MuSK-IgG positivity by radioimmunoprecipitation assay; and (2) residency in the district of Sassari. Incidence (January 2010-December 2019) and prevalence (December 31, 2019) were calculated. RESULTS: A total of 202 patients were included (incident, 107; prevalent, 180). Antibody specificities were AChR (n = 187 [93%]) and MuSK (n = 15 [7%]). The crude MG incidence (95% confidence interval) was 32.6 (26.8-39.2)/million, while prevalence was 55.3 (47.7-63.9)/100,000. After age-standardization to the world population, incidence decreased to 18.4 (14.3-22.5)/million, while prevalence decreased to 31.6 (26.1-37.0)/100,000. Among incident cases, age strata (years) at MG onset were: <18 (2%), 18-49 (14%), 50-64 (21%), and ≥65 (63%). DISCUSSION: Sardinia is a high-risk region for MG, with a prevalence that exceeds the European threshold for rare disease. Identification of the environmental and genetic determinants of this risk may improve our understanding of disease pathophysiology.

Clinical application of ultra-high frequency ultrasound: Discovering a new imaging frontier.

The ultra-high frequency ultrasound (UHFUS) is characterized by the use of probes between 30 and 100 MHz. This technology has recently been introduced in clinical practice and represents an opportunity for the diagnosis of numerous pathologies. The high spatial resolution of UHFUS, up to 30 µ in pixel size, allows to study the pathological modifications and to guide microsurgery treatments in anatomical body structures not evaluable by conventional HFUS. The aim of this work is to provide a review of the literature on the current clinical applications of UHFUS and to discuss its added role in different clinical settings.

Cardiac and Neuromuscular Features of Patients With LMNA-Related Cardiomyopathy.

Background: Mutations in the LMNA (lamin A/C) gene have been associated with neuromuscular and cardiac manifestations, but the clinical implications of these signs are not well understood. Objective: To learn more about the natural history of LMNA-related disease. Design: Observational study. Setting: 13 clinical centers in Italy from 2000 through 2018. Patients: 164 carriers of an LMNA mutation. Measurements: Detailed cardiologic and neurologic evaluation at study enrollment and for a median of 10 years of follow-up. Results: The median age at enrollment was 38 years, and 51% of participants were female. Neuromuscular manifestations preceded cardiac signs by a median of 11 years, but by the end of follow-up, 90% of the patients had electrical heart disease followed by structural heart disease. Overall, 10 patients (6%) died, 14 (9%) received a heart transplant, and 32 (20%) had malignant ventricular arrhythmias. Fifteen patients had gait loss, and 6 had respiratory failure. Atrial fibrillation and second- and third-degree atrioventricular block were observed, respectively, in 56% and 51% of patients with combined cardiac and neuromuscular manifestations and 37% and 33% of those with heart disease only. Limitations: Some of the data were collected retrospectively. Neuromuscular manifestations were more frequent in this analysis than in previous studies. Conclusion: Many patients with an LMNA mutation have neurologic symptoms by their 30s and develop progressive cardiac manifestations during the next decade. A substantial proportion of these patients will have life-threatening neurologic or cardiologic conditions. Primary Funding Source: None.

Videofluorography swallow study in patients with systemic sclerosis: correlation with clinical and radiological features.

OBJECTIVES: The aim of our study was to assess the role of videofluorography (VFG) in the evaluation of swallowing and oesophageal peristalsis in patients with systemic sclerosis (SSc). METHODS: From June 2014 to September 2017, 55 consecutive SSc patients, defined according to the 2013 ACR/EULAR classification criteria, underwent VFG study using a remote-controlled digital device. In order to evaluate possible abnormalities, 18 dynamic parameters were chosen, dividing the act of swallowing into three phases: oral, pharyngeal and oesophageal phases. The following dynamic radiological findings were considered: veil motility in phonation, leakage, drooling, salivation and presence of residues in the oral cavity, pharyngeal residues, penetration, aspiration, altered motility of the upper oesophageal sphincter, efficacy of primary peristaltic contractions, oesophageal clearance capacity, reflux, oesophagitis and motility of the lower oesophageal sphincter. RESULTS: The VFG study was well tolerated in all patients. Dysfunctions of oesophageal motility were common and included abnormal motility of UES (12.7%) and LES (76.4%), inadequate primary peristalsis (52.7%), abnormal secondary peristalsis (29.1%) and non-peristaltic contractions (40%). A defective oesophageal clearance was observed in 69.4% of patients. Moreover, most patients presented signs of oesophageal reflux (63.6%), oesophagitis (81.8%) and hiatal hernia (80%). Pharyngeal abnormalities were less common and involved up to 50% of patients. Oesophageal dysfunction and defective clearance were associated with dcSSc and pulmonary involvement. CONCLUSIONS: The VFG study is a useful technique for the morphological and functional evaluation of swallowing in SSc patients.

Muscle magnetic resonance imaging in congenital myasthenic syndromes.

INTRODUCTION: In this study we investigated muscle magnetic resonance imaging in congenital myasthenic syndromes (CMS). METHODS: Twenty-six patients with 9 CMS subtypes and 10 controls were imaged. T1-weighted (T1w) and short-tau inversion recovery (STIR) 3-Tesla MRI images obtained at thigh and calf levels were scored for severity. RESULTS: Overall mean the T1w score was increased in GFPT1 and DPAGT1 CMS. T1w scans of the AChR-deficiency, COLQ, and CHAT subjects were indistinguishable from controls. STIR images from CMS patients did not differ significantly from those of controls. Mean T1w score correlated with age in the CMS cohort. CONCLUSIONS: MRI appearances ranged from normal to marked abnormality. T1w images seem to be especially abnormal in some CMS caused by mutations of proteins involved in the glycosylation pathway. A non-selective pattern of fat infiltration or a normal-appearing scan in the setting of significant clinical weakness should suggest CMS as a potential diagnosis. Muscle MRI could play a role in differentiating CMS subtypes. Muscle Nerve 54: 211-219, 2016.

Influence of treatments in multiple sclerosis disability: a cohort study.

BACKGROUND AND OBJECTIVE: A critical aspect of multiple sclerosis (MS) treatments is understanding the effect of disease-modifying drugs (DMDs) on the long-term risk of disability and whether the effect is related to disability at start of treatment. METHODS: We performed an observational study on 3060 MS patients. The effect of therapy on progression to Expanded Disability Status Scale (EDSS) 3.0 and 6.0 from onset was analysed in treated vs untreated (UTP) patients using Cox regression analysis adjusted for propensity score and immortal time bias. RESULTS: Compared to UTP, the risks of EDSS 3.0 were 94% and 73% lower in immunomodulant (IMTP-) and immunosuppressant (ISTP-) treated patients, respectively, while the risk of EDSS 6.0 was 86% lower in IMTP. The risk of EDSS 6.0 was, respectively, 91% and 75% lower in 1275 IMTP before and 114 after EDSS 3.0 than in 539 UTP; the risk was higher in IMTP starting therapy after EDSS 3.0 than before (HR = 4.42). CONCLUSIONS: DMDs delayed long-term disability in MS patients treated either in the early or, to a lesser extent, in the later phase of the disease. Thus, the window of therapeutic opportunity is relatively extended, assuming that early is better than late treatment, but late is better than never.

Congenital myasthenic syndromes due to mutations in ALG2 and ALG14.

Congenital myasthenic syndromes are a heterogeneous group of inherited disorders that arise from impaired signal transmission at the neuromuscular synapse. They are characterized by fatigable muscle weakness. We performed linkage analysis, whole-exome and whole-genome sequencing to determine the underlying defect in patients with an inherited limb-girdle pattern of myasthenic weakness. We identify ALG14 and ALG2 as novel genes in which mutations cause a congenital myasthenic syndrome. Through analogy with yeast, ALG14 is thought to form a multiglycosyltransferase complex with ALG13 and DPAGT1 that catalyses the first two committed steps of asparagine-linked protein glycosylation. We show that ALG14 is concentrated at the muscle motor endplates and small interfering RNA silencing of ALG14 results in reduced cell-surface expression of muscle acetylcholine receptor expressed in human embryonic kidney 293 cells. ALG2 is an alpha-1,3-mannosyltransferase that also catalyses early steps in the asparagine-linked glycosylation pathway. Mutations were identified in two kinships, with mutation ALG2p.Val68Gly found to severely reduce ALG2 expression both in patient muscle, and in cell cultures. Identification of DPAGT1, ALG14 and ALG2 mutations as a cause of congenital myasthenic syndrome underscores the importance of asparagine-linked protein glycosylation for proper functioning of the neuromuscular junction. These syndromes form part of the wider spectrum of congenital disorders of glycosylation caused by impaired asparagine-linked glycosylation. It is likely that further genes encoding components of this pathway will be associated with congenital myasthenic syndromes or impaired neuromuscular transmission as part of a more severe multisystem disorder. Our findings suggest that treatment with cholinesterase inhibitors may improve muscle function in many of the congenital disorders of glycosylation.

Genetic and clinical characteristics of skeletal and cardiac muscle in patients with lamin A/C gene mutations.

Alterations of the lamin A/C (LMNA) gene are associated with different clinical entities, including disorders that affect skeletal and cardiac muscle, peripheral nerves, metabolism, bones, and disorders that cause premature aging. In this article we review the clinical and genetic characteristics of cardiac and skeletal muscle diseases related to alterations in the LMNA gene. There is no single explanation of how LMNA gene alterations may cause these disorders; however, important goals have been achieved in understanding the pathogenic effects of LMNA gene mutations on cardiac and skeletal muscle.

Advances in basic and clinical research in laminopathies.

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.

Overlapping syndromes in laminopathies: a meta-analysis of the reported literature.

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.

Unusual clinical presentations in subjects carrying novel NOTCH3 gene mutations.

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a disease caused by alterations in the NOTCH3 gene. METHODS: We describe the clinical, instrumental, and genetic findings in CADASIL patients who carry novel NOTCH3 gene mutations. RESULTS AND CONCLUSIONS: This study broadens the spectrum of clinical manifestations and genetic alterations associated with this disease.

White matter abnormalities in 15 subjects with SPG76.

BACKGROUND AND OBJECTIVES: Hereditary spastic paraplegias (HSPs) are heterogenous genetic disorders characterized by progressive pyramidal tract involvement. SPG76 is a recently identified form of HSP, caused by biallelic calpain-1 (CAPN1) variants. The most frequently described MRI abnormality in SPG76 is mild cerebellar atrophy and non-specific white matter abnormalities were reported in only one case. Following the identification of prominent white matter abnormalities in a subject with CAPN1 variants, which delayed the diagnosis, we aimed to verify the presence of MRI patterns of white matter involvement specific to this HSP. METHODS: We performed a retrospective radiological qualitative analysis of 15 subjects with SPG76 (4 previously unreported) initially screened for white matter involvement. Moreover, we performed quantitative analyses in our proband with available longitudinal studies. RESULTS: We observed bilateral, periventricular white matter involvement in 12 subjects (80%), associated with multifocal subcortical abnormalities in 5 of them (33.3%). Three subjects (20%) presented only multifocal subcortical involvement. Longitudinal quantitative analyses of our proband revealed increase in multifocal white matter lesion count and increased area of periventricular white matter involvement over time. DISCUSSION: SPG76 should be added to the list of HSPs with associated white matter abnormalities. We identified periventricular white matter involvement in subjects with SPG76, variably associated with multifocal subcortical white matter abnormalities. These findings, in the presence of progressive spastic paraparesis, can mislead the diagnostic process towards an acquired white matter disorder.

Prevalence of Spinal Muscular Atrophy in the Era of Disease-Modifying Therapies: An Italian Nationwide Survey.

OBJECTIVE: Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in the SMN1 gene. The aim of this study was to assess the prevalence of SMA and treatment prescription in Italy. METHODS: An online survey was distributed to 36 centers identified by the Italian government as referral centers for SMA. Data on the number of patients with SMA subdivided according to age, type, SMN2 copy number, and treatment were collected. RESULTS: One thousand two hundred fifty-five patients with SMA are currently followed in the Italian centers with an estimated prevalence of 2.12/100,000. Of the 1,255, 284 were type I, 470 type II, 467 type III, and 15 type IV with estimated prevalence of 0.48, 0.79, 0.79 and 0.02/100,000, respectively. Three patients with SMA 0 and 16 presymptomatic patients were also included. Approximately 85% were receiving one of the available treatments. The percentage of treated patients decreased with decreasing severity (SMA I: 95.77%, SMA II: 85.11%, SMA III: 79.01%). DISCUSSION: The results provide for the first time an estimate of the prevalence of SMA at the national level and the current distribution of patients treated with the available therapeutical options. These data provide a baseline to assess future changes in relation to the evolving therapeutical scenario.

Cardiac involvement in patients with lamin A/C gene mutations: a cohort observation.

INTRODUCTION: LMNA gene mutations are associated with cardiac and skeletal muscle alterations. METHODS: A cohort of 21 mutated individuals was assessed with clinical and instrumental investigations over the years. RESULTS: The median observation period was 6 years. Cardiac compromise was detected in 16 patients. Bradyarrhythmias were the most frequent manifestations, followed by supraventricular arrhythmias. Two individuals suffered from nonsustained and 1 from sustained ventricular tachyarrhythmias. Dilated cardiomyopathy was detected in 3 patients. Evaluation of the frequencies of the clinical expressions showed a high probability of suffering from analogue heart compromise in study subjects bearing the same LMNA gene mutation. CONCLUSIONS: Cardiac involvement represents a very common phenotypic expression of LMNA gene mutation. Subjects sharing common genetic background seem to suffer from analogue pattern of cardiac manifestation.

O2-O3 chemodiscolysis: How much, how long? Retrospective outcome evaluation of different treatment sessions in partially-responder patients.

PURPOSE: To retrospectively evaluate the clinical and instrumental outcome of different treatment sessions of oxygen-ozone (O2-O3) chemodiscolysis in patients with lumbar disc herniation. METHODS: We evaluated 73 patients partially responders to a single session of oxygen-ozone (O2-O3) chemodiscolysis and submitted to multiple injections sessions. All patients completed a pre- and post-treatment clinical (VAS and modified McNab score) and instrumental MRI follow-up. Imaging evaluation included assessment of intervertebral disc area (IDA). Pre- and post-treatment differences were compared to evaluate differences in variation between groups. Correlation analysis was used to evaluate the relationship between morphological and clinical parameters. RESULTS: Based on the type and number of treatments performed, patients were divided into three groups: Group A) patients submitted to an additional periradicular anaesthetic/steroid injection; Group B) patients submitted to an additional session of intradiscal O2-O3 injection; Group C) patients submitted to two further sessions of intradiscal O2-O3 injection.The results showed an improvement of pain scores in all groups, and a smaller disc area change in group B. Comparing the differences between pre- and post-treatment features among the three different groups of patients, we did not find any statistically significant difference. Correlation analysis did not show any statistically significant correlation between the morphological changes of the intervertebral disc and the clinical output scores. CONCLUSIONS: In our retrospective observation of partially responder patients, multiple intradiscal ozone injections were not associated with a higher disc shrinkage nor superior clinical outcome compared to a single intradiscal O2-O3 application with an additional periradicular injection session.

Epidemiology of multiple sclerosis in south-western Sardinia.

BACKGROUND: Sardinia is a known high-risk area for multiple sclerosis (MS), but no data for south-western Sardinia (SWS) are available. SWS has a genetically homogeneous population, apart from St Peter Island, and represents a peculiar environment related to the industrial, mineralogical and military economy. OBJECTIVE: To estimate prevalence and incidence and to evaluate temporal trends and geographical distribution of MS in SWS. METHODS: MS prevalence was evaluated on 31 December 2007 and crude mean annual incidence rate was defined between 2003 and 2007. Temporal trend in MS incidence was assessed using the Armitage test. To identify MS clusters, Standard Morbidity Ratio (SMR) was calculated for each village and geographical distribution prevalence by means of a Bayesian hierarchical model. RESULTS: Total crude prevalence rate was 210.4 (95% CI 186.3-234.5): 280.3 (95% CI 241.4-319.3) for females, 138 (95% CI 110.1-165.8) for males. The crude mean annual incidence rate was 9.7/100,000 (95% CI 3.4-13.2): 4.7/100,000 (95% CI 2.4-17.0) and 14.6/100,000 (95% CI 11.8-34.8) for males and females respectively. MS incidence has increased over the last 50 years. Cluster analysis showed an SMR of 0.2 (95% CI 0.05-0.68, p = 0.002) on the island of San Pietro, and 2.0 (95% CI 1.35-2.95, p = 0.001) in Domusnovas. Spatial distribution of MS was confirmed by Bayesian geographical analysis. CONCLUSIONS: Our data confirm Sardinia as a high-risk area for MS and support the relevance of genetic factors in MS, as evidenced in St Peter Island. However, we found an unexpectedly high MS prevalence in one village, in particular in males, suggesting an environmental influence on MS occurrence.

Dilated cardiomyopathy with conduction defects in a patient with partial merosin deficiency due to mutations in the laminin-α2-chain gene: a chance association or a novel phenotype?

Patients with a partial reduction of merosin due to mutations in the laminin-α2 chain gene usually present with a mild form of congenital muscular dystrophy or a limb-girdle-like muscular dystrophy. To our knowledge, cardiac impairment has never been reported in such patients. A longitudinal study of a patient with partial laminin-α2 deficiency secondary to mutations in the LAMA2 gene revealed dilated cardiomyopathy with ventricular arrhythmias. Is this a chance association or a novel phenotype?

Aberrant splicing in the LMNA gene caused by a novel mutation on the polypyrimidine tract of intron 5.

INTRODUCTION: Familial dilated cardiomyopathy with conduction system defects variably associated with skeletal muscle abnormalities is frequently caused by LMNA gene mutations. METHODS: A family affected by cardiac abnormalities, either isolated or variably associated with skeletal muscle compromise, was identified. LMNA gene analysis was applied to all family members. RESULTS: A novel intron 5 (c.937-11 C > G) mutation was identified. mRNA transcription analysis was subsequently performed, and cDNA was obtained from mutated patients. It displayed an aberrant splice product featuring the insertion of 40 nucleotides from intron 5, leading to a frameshift. Computational predictions identified a cryptic splice site 40 bp upstream from the canonical site; this alternative splicing event was elicited by intronic mutation, which seems to interfere with the polypyrimidine tract of the canonical site. CONCLUSIONS: We have described the first mutation on the LMNA gene interfering with the polypyrimidine tract. Our findings underline the importance of including introns in the search for mutations.

Clinical and molecular characterization of limb-girdle muscular dystrophy due to LAMA2 mutations.

INTRODUCTION: In this study we describe the clinical and molecular characteristics of limb-girdle muscular dystrophy (LGMD) due to LAMA2 mutations. METHODS: Five patients clinically diagnosed with LGMD and showing brain white matter hyperintensities on MRI were evaluated using laminin α2 genetic and protein testing. RESULTS: The patients had slowly progressive, mild muscular dystrophy with various degrees of CNS involvement. Epilepsy was observed in 2, and subtle symptoms of CNS involvement (mild deficit in executive functions and low IQ scores) were noted in 3 patients. Novel LAMA2 mutations were identified in all patients. The amount of laminin α2 protein in the muscle biopsies ranged from trace to about 50% compared with controls. CONCLUSIONS: This study represents the largest series of LGMD laminin α2-deficient patients and expands the clinical phenotype associated with LAMA2 mutations. The findings suggest that brain MRI could be included in the diagnostic work-up of patients with undiagnosed LGMD.

Muscle imaging analogies in a cohort of patients with different clinical phenotypes caused by LMNA gene mutations.

Laminopathies are a heterogeneous group of LMNA-gene-mutation-related clinical disorders associated with alterations of cardiac and skeletal muscle and peripheral nerves, metabolic defects, and premature aging. Leg muscle imaging investigations were performed in a cohort of patients with LMNA gene alterations who were suffering from Emery-Dreifuss muscular dystrophy, limb-girdle muscular dystrophy type 1B, isolated cardiac disorders or a phenotype of cardiac disorders, and lipodystrophy, including one individual with peripheral neuropathy. Leg muscle imaging revealed varying degrees of alteration in the soleus and medial head of gastrocnemius in each subject. This study demonstrates that LMNA-gene-mutated patients devoid of any clinically detectable skeletal muscle involvement have the same pattern of leg muscle involvement as patients with overt skeletal muscle compromise. This finding suggests the presence of a continuum of skeletal muscle involvement among phenotypes of LMNA-gene-mutation-related skeletalmyopathy and cardiomyopathy.