Facioscapulohumeral muscular dystrophy and occurrence of heart arrhythmia

Hospital admissions from the emergency department of adult patients affected by myopathies

BACKGROUND AND PURPOSE

Myopathies are associated with classic signs and symptoms, but also with possible life-threatening complications that may require assistance in an emergency setting. This phenomenon is understudied in the literature. We aimed to assess the presentation, management, and outcomes of clinical manifestations potentially related to a muscle disorder requiring referral to the adult emergency department (ED) and hospitalization.

METHODS

Anonymized patient data retrieved using the International Classification of Diseases, Ninth Revision codes related to muscle disorders over 4 years were retrospectively analyzed. Medical reports were evaluated to extract demographic and clinical variables, along with outcomes. Two groups were defined based on the presence (known diagnosis [KD] group) or absence (unknown diagnosis [UD] group) of a diagnosed muscle disorder at arrival.

RESULTS

A total of 244 patients were included, 51% of whom were affected by a known myopathy, predominantly limb-girdle muscular dystrophies and myotonic dystrophies. The main reasons for ED visits in the KD group were respiratory issues, worsening of muscle weakness, and gastrointestinal problems. Heart complications were less prevalent. In the UD group, 27 patients received a new diagnosis of a specific primary muscle disorder after the ED access, mostly an inflammatory myopathy. Death during hospitalization was recorded in 26 patients, with a higher rate in the KD group and in patients affected by mitochondrial and inflammatory myopathies. Sepsis and dyspnea were associated with increased death risk.

CONCLUSIONS

Respiratory complications are the most common reason for myopathic patients accessing the ED, followed by gastrointestinal issues. Infections are severe threats and, once hospitalized, these patients have relatively high mortality.

Management of scapular dysfunction in facioscapulohumeral muscular dystrophy: the biomechanics of winging, arthrodesis indications, techniques and outcomes

Facioscapulohumeral muscular dystrophy (FSHD) is a common hereditary disorder which typically results in scapular winging due to wasting of the periscapular muscles affected by this condition. Scapulothoracic arthrodesis (STA) is the current surgical treatment for FSHD patients with severe winging and preserved deltoid muscle. There are several different techniques in the literature such as multifilament cables alone and cable or cerclage wires combined with single or multiple plates. We prefer cables without plates as it provides independent strong fixation points and strongly recommend utilization of autograft. The functional results of studies report that regardless of the technique used, shoulder elevation and thus quality of life is improved, as shown with outcome scores. There are several complications associated with STA. Pulmonary complications are common and usually resolve spontaneously. Meticulous surgical technique and effective postoperative analgesia may reduce the incidence. Scapular complications which are associated with the fixation may be encountered in the early or late period, which are related to the learning curve of the surgeon. In conclusion, STA is a reliable solution to a major problem in FSHD patients that helps them maintain their activities of daily living until a cure for the disease is found. A successful result is strongly dependent on patient selection, and a multidisciplinary team of neurologists, geneticists and orthopaedic surgeons is required to achieve good results.

2022 HRS expert consensus statement on evaluation and management of arrhythmic risk in neuromuscular disorders

This international multidisciplinary document is intended to guide electrophysiologists, cardiologists, other clinicians, and health care professionals in caring for patients with arrhythmic complications of neuromuscular disorders (NMDs). The document presents an overview of arrhythmias in NMDs followed by detailed sections on specific disorders: Duchenne muscular dystrophy, Becker muscular dystrophy, and limb-girdle muscular dystrophy type 2; myotonic dystrophy type 1 and type 2; Emery-Dreifuss muscular dystrophy and limb-girdle muscular dystrophy type 1B; facioscapulohumeral muscular dystrophy; and mitochondrial myopathies, including Friedreich ataxia and Kearns-Sayre syndrome, with an emphasis on managing arrhythmic cardiac manifestations. End-of-life management of arrhythmias in patients with NMDs is also covered. The document sections were drafted by the writing committee members according to their area of expertise. The recommendations represent the consensus opinion of the expert writing group, graded by class of recommendation and level of evidence utilizing defined criteria. The recommendations were made available for public comment; the document underwent review by the Heart Rhythm Society Scientific and Clinical Documents Committee and external review and endorsement by the partner and collaborating societies. Changes were incorporated based on these reviews. By using a breadth of accumulated available evidence, the document is designed to provide practical and actionable clinical information and recommendations for the diagnosis and management of arrhythmias and thus improve the care of patients with NMDs.

ANT1 overexpression models: Some similarities with facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disorder characterized by progressive muscle weakness. Adenine nucleotide translocator 1 (ANT1), the only 4q35 gene involved in mitochondrial function, is strongly expressed in FSHD skeletal muscle biopsies. However, its role in FSHD is unclear. In this study, we evaluated ANT1 overexpression effects in primary myoblasts from healthy controls and during Xenopus laevis organogenesis. We also compared ANT1 overexpression effects with the phenotype of FSHD muscle cells and biopsies. Here, we report that the ANT1 overexpression-induced phenotype presents some similarities with FSHD muscle cells and biopsies. ANT1-overexpressing muscle cells showed disorganized morphology, altered cytoskeletal arrangement, enhanced mitochondrial respiration/glycolysis, ROS production, oxidative stress, mitochondrial fragmentation and ultrastructure alteration, as observed in FSHD muscle cells. ANT1 overexpression in Xenopus laevis embryos affected skeletal muscle development, impaired skeletal muscle, altered mitochondrial ultrastructure and led to oxidative stress as observed in FSHD muscle biopsies. Moreover, ANT1 overexpression in X. laevis embryos affected heart structure and mitochondrial ultrastructure leading to cardiac arrhythmia, as described in some patients with FSHD. Overall our data suggest that ANT1 could contribute to mitochondria dysfunction and oxidative stress in FSHD muscle cells by modifying their bioenergetic profile associated with ROS production. Such interplay between energy metabolism and ROS production in FSHD will be of significant interest for future prospects.

Baroreflex sensitivity in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD), a common form of muscular dystrophy, is caused by a genetic mutation that alters DUX4 gene expression. This mutation contributes to significant skeletal muscle loss. Although it is suggested that cardiac muscle may be spared, people with FSHD have demonstrated autonomic dysregulation. It is unknown if baroreflex function, an important regulator of blood pressure (BP), is impaired in people with FSHD. We examined if baroreflex sensitivity (BRS) is blunted in patients with FSHD. Thirty minutes of resting BP, heart rate, and cardiovagal BRS were measured in 13 patients with FSHD (age: 50 ± 13 years, avg ± SD) and 17 sex- and age-matched controls (age: 47 ± 14 years, p > 0.05). People with FSHD were less active (Activity Metabolic Index, AMI) (FSHD: 24 ± 30; controls: 222 ± 175 kcal/day; p < 0.001) but had a similar body mass index compared with controls (FSHD: 27 ± 4; controls: 27 ± 4 kg/m2 ; p > 0.05). BRSup (hypertensive response), BRSdown (hypotensive response), and total BRS were similar between groups (BRSup: FSHD: 12 ± 8; controls: 12 ± 5 ms/mmHg; BRSdown: FSHD: 10 ± 4; controls: 13 ± 6 ms/mmHg; BRS: FSHD: 14 ± 9; controls: 13 ± 6 ms/mmHg; p > 0.05). Mean arterial pressure was similar between groups (FSHD: 96 ± 7; controls: 91 ± 6mmHg). Individuals with FSHD had an elevated heart rate compared with controls (FSHD: 65 ± 8; controls: 59 ± 8 BPM; p = 0.03), but when co-varied for AMI, this relationship disappeared (p = 0.39). These findings suggest that BRS is not attenuated in people with FSHD, but an elevated heart rate may be due to low physical activity levels, a potential consequence of limited mobility.

Systemic Manifestations and Symptom Burden of Facioscapulohumeral Muscular Dystrophy in a Referral Cohort

INTRODUCTION/AIMS

The full spectrum of the clinical phenotype of facioscapulohumeral muscular dystrophy (FSHD), beyond skeletal muscle weakness, remains poorly characterized. In this study, we describe systemic manifestations and symptom burden in a large series of FSHD patients.

METHODS

We performed a retrospective chart review of FSHD patients seen at our institution between 2000 and 2017. We reviewed patients' responses to a comprehensive review of symptoms and the results of diagnostic testing for sensorineural hearing loss, cardiac disease, dysphagia, ocular abnormalities, and respiratory insufficiency. We assessed the association between disease manifestations and age of onset, genetic profile, and disease duration.

RESULTS

We identified 87 patients with FSHD. The most common reported symptoms included pain (71%), difficulty sleeping (41%), headaches (27%), and altered mood (24%). When tested, 7/16 (44%) patients had sensorineural hearing loss, 20/60 (33%) had cardiac arrhythmias or conduction defects, 17/45 (38%) had echocardiogram abnormalities, 12/25 (48%) had reduced forced vital capacity, and 4/10 (40%) had oropharyngeal dysphagia. However, patients with these abnormalities represented 8%, 23%, 20%, 14%, and 5% of total number of patients respectively, as uniform screening was lacking. Ocular pathology attributable to FSHD was not detected.

DISCUSSION

FSHD demonstrates a broad clinical phenotype. Increased vigilance among neurologists to screen for systemic manifestations of the disease is warranted. More uniform screening and future population-based studies are needed to compare the findings in FSHD patients to the general population.

Progressive myocardial injury in myotonic dystrophy type II and facioscapulohumeral muscular dystrophy 1: a cardiovascular magnetic resonance follow-up study

AIM

Muscular dystrophy (MD) is a progressive disease with predominantly muscular symptoms. Myotonic dystrophy type II (MD2) and facioscapulohumeral muscular dystrophy type 1 (FSHD1) are gaining an increasing awareness, but data on cardiac involvement are conflicting. The aim of this study was to determine a progression of cardiac remodeling in both entities by applying cardiovascular magnetic resonance (CMR) and evaluate its potential relation to arrhythmias as well as to conduction abnormalities.

METHODS AND RESULTS

83 MD2 and FSHD1 patients were followed. The participation was 87% in MD2 and 80% in FSHD1. 1.5 T CMR was performed to assess functional parameters as well as myocardial tissue characterization applying T1 and T2 mapping, fat/water-separated imaging and late gadolinium enhancement. Focal fibrosis was detected in 23% of MD2) and 33% of FSHD1 subjects and fat infiltration in 32% of MD2 and 28% of FSHD1 subjects, respectively. The incidence of all focal findings was higher at follow-up. T2 decreased, whereas native T1 remained stable. Global extracellular volume fraction (ECV) decreased similarly to the fibrosis volume while the total cell volume remained unchanged. All patients with focal fibrosis showed a significant increase in left ventricular (LV) and right ventricular (RV) volumes. An increase of arrhythmic events was observed. All patients with ventricular arrhythmias had focal myocardial changes and an increased volume of both ventricles (LV end-diastolic volume (EDV) p = 0.003, RVEDV p = 0.031). Patients with supraventricular tachycardias had a significantly higher left atrial volume (p = 0.047).

CONCLUSION

We observed a remarkably fast and progressive decline of cardiac morphology and function as well as a progression of rhythm disturbances, even in asymptomatic patients with a potential association between an increase in arrhythmias and progression of myocardial tissue damage, such as focal fibrosis and fat infiltration, exists. These results suggest that MD2 and FSHD1 patients should be carefully followed-up to identify early development of remodeling and potential risks for the development of further cardiac events even in the absence of symptoms. Trial registration ISRCTN, ID ISRCTN16491505. Registered 29 November 2017 - Retrospectively registered, http://www.isrctn.com/ISRCTN16491505.

PAX7 target gene repression associates with FSHD progression and pathology over 1 year

Facioscapulohumeral muscular dystrophy (FSHD) is a prevalent, inherited skeletal myopathy linked to hypomethylation of the D4Z4 macrosatellite at chromosome 4q35. This epigenetic de-repression permits expression of the transcription factor DUX4, which may drive pathology by direct activation of target genes or through inhibition of the homologous transcription factor PAX7. We demonstrated that PAX7 target gene repression is a superior biomarker of FSHD status compared with DUX4 target gene expression. However, despite importance for clinical trials, there remains no transcriptomic biomarker for FSHD progression. A recent study by Wong et al. [Longitudinal measures of RNA expression and disease activity in FSHD muscle biopsies. Hum. Mol. Genet., 29, 1030-1043] performed MRI, muscle biopsy transcriptomics and histopathology on a cohort of FSHD patients with 1-year follow-up. No significant changes in any biomarkers were reported over this time period. However, the authors did not consider PAX7 target gene repression as a marker of FSHD progression. Here we demonstrate that PAX7 target gene repression increases in these paired FSHD samples from year 1 to year 2 and is thus a marker of FSHD progression over 1 year. Moreover, we show that three validated DUX4 target gene expression biomarkers are not associated with FSHD progression over 1 year. We further confirm that PAX7 target gene repression associates with clinical correlates of FSHD disease activity, measured by MRI and histopathology. Thus, PAX7 target gene repression is a uniquely sensitive biomarker of FSHD progression and pathology, valid over a 1 year time frame, implicating its use in clinical trials.

DUX4 expressing immortalized FSHD lymphoblastoid cells express genes elevated in FSHD muscle biopsies, correlating with the early stages of inflammation

Facioscapulohumeral muscular dystrophy (FSHD) is an incurable disorder linked to ectopic expression of DUX4. However, DUX4 is notoriously difficult to detect in FSHD muscle cells, while DUX4 target gene expression is an inconsistent biomarker for FSHD skeletal muscle biopsies, displaying efficacy only on pathologically inflamed samples. Immune gene misregulation occurs in FSHD muscle, with DUX4 target genes enriched for those associated with inflammatory processes. However, there lacks an assessment of the FSHD immune cell transcriptome, and its contribution to gene expression in FSHD muscle biopsies. Here, we show that EBV-immortalized FSHD lymphoblastoid cell lines express DUX4 and both early and late DUX4 target genes. Moreover, a biomarker of 237 up-regulated genes derived from FSHD lymphoblastoid cell lines is elevated in FSHD muscle biopsies compared to controls. The FSHD Lymphoblast score is unaltered between FSHD myoblasts/myotubes and their controls however, implying a non-myogenic cell source in muscle biopsies. Indeed, the FSHD Lymphoblast score correlates with the early stages of muscle inflammation identified by histological analysis on muscle biopsies, while our two late DUX4 target gene expression biomarkers associate with macroscopic inflammation detectable via MRI. Thus, FSHD lymphoblastoid cell lines express DUX4 and early and late DUX4 target genes, therefore, muscle-infiltrated immune cells may contribute the molecular landscape of FSHD muscle biopsies.

Role of CMR Imaging in Diagnostics and Evaluation of Cardiac Involvement in Muscle Dystrophies

PURPOSE OF REVIEW

This review aims to outline the utility of cardiac magnetic resonance (CMR) in patients with different types of muscular dystrophies for the assessment of myocardial involvement, risk stratification and in guiding therapeutic decisions.

RECENT FINDINGS

In patients suffering from muscular dystrophies (MD), even mild initial dysfunction may lead to severe heart failure over a time course of years. CMR plays an increasing role in the diagnosis and clinical care of these patients, mostly due to its unique capability to precisely characterize subclinical and progressive changes in cardiac geometry, function in order to differentiate myocardial injury it allows the identification of inflammation, focal and diffuse fibrosis as well as fatty infiltration. CMR may provide additional information in addition to the physical examination, laboratory tests, ECG, and echocardiography. Further trials are needed to investigate the potential impact of CMR on the therapeutic decision-making as well as the assessment of long-term prognosis in different forms of muscular dystrophies. In addition to the basic cardiovascular evaluation, CMR can provide a robust, non-invasive technique for the evaluation of subclinical myocardial tissue injury like fat infiltration and focal and diffuse fibrosis. Furthermore, CMR has a unique capability to detect the progression of myocardial tissue damage in patients with a preserved systolic function.

Facioscapulohumeral muscular dystrophy-Reproductive counseling, pregnancy, and delivery in a complex multigenetic disease

Reproductive counseling in facioscapulohumeral muscular dystrophy (FSHD) can be challenging due to the complexity of its underlying genetic mechanisms and due to incomplete penetrance of the disease. Full understanding of the genetic causes and potential inheritance patterns of both distinct FSHD types is essential: FSHD1 is an autosomal dominantly inherited repeat disorder, whereas FSHD2 is a digenic disorder. This has become even more relevant now that prenatal diagnosis and preimplantation genetic diagnosis options are available for FSHD1. Pregnancy and delivery outcomes in FSHD are usually favorable, but clinicians should be aware of the risks. We aim to provide clinicians with case‐based strategies for reproductive counseling in FSHD, as well as recommendations for pregnancy and delivery.

Cardiac Involvement in Facioscapulohumeral Muscular Dystrophy (FSHD)

Background: Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common muscular dystrophies and predominantly affects facial and shoulder girdle muscles. Previous case reports and cohort studies identified minor cardiac abnormalities in FSHD patients, but their nature and frequency remain incompletely characterized. Methods: We reviewed cardiac, neurological and genetic findings of 104 patients with genetically confirmed FSHD. Results: The most common conduction abnormality was complete (7%) or incomplete (5%) right bundle branch block (RBBB). Bifascicular block, left anterior fascicular block, complete atrioventricular block, and 2:1 atrioventricular block each occurred in 1% of patients. Atrial fibrillation or flutter were seen in 5% of patients. Eight percent of patients had heart failure with reduced ejection fraction and 25% had valvular disease. The latter included aortic stenosis in 6% (severe in 4% and moderate in 2%) and moderate aortic regurgitation in 8%. Mitral valve prolapse (MVP) was present in 9% of patients without significant mitral regurgitation. There were no significant associations between structural or conduction abnormalities and age, degree of muscle weakness, or size of the 4q deletion. Conclusions: Both structural and conduction abnormalities can occur in FSHD. The most common abnormalities are benign (RBBB and MVP), but more significant cardiac involvement was also observed. The presence of cardiac abnormalities cannot be predicted from the severity of the neurological phenotype, nor from the genotype.

Targeted epigenetic repression by CRISPR/dSaCas9 suppresses pathogenic DUX4-fl expression in FSHD

Facioscapulohumeral muscular dystrophy (FSHD) is caused by incomplete silencing of the disease locus, leading to pathogenic misexpression of DUX4 in skeletal muscle. Previously, we showed that CRISPR inhibition could successfully target and repress DUX4 in FSHD myocytes. However, an effective therapy will require both efficient delivery of therapeutic components to skeletal muscles and long-term repression of the disease locus. Thus, we re-engineered our platform to allow in vivo delivery of more potent epigenetic repressors. We designed an FSHD-optimized regulatory cassette to drive skeletal muscle-specific expression of dCas9 from Staphylococcus aureus fused to HP1α, HP1γ, the MeCP2 transcriptional repression domain, or the SUV39H1 SET domain. Targeting each regulator to the DUX4 promoter/exon 1 increased chromatin repression at the locus, specifically suppressing DUX4 and its target genes in FSHD myocytes and in a mouse model of the disease. Importantly, minimizing the regulatory cassette and using the smaller Cas9 ortholog allowed our therapeutic cassettes to be effectively packaged into adeno-associated virus (AAV) vectors for in vivo delivery. By engineering a muscle-specific epigenetic CRISPR platform compatible with AAV vectors for gene therapy, we have laid the groundwork for clinical use of dCas9-based chromatin effectors in skeletal muscle disorders.

Facioscapulohumeral muscular dystrophy 1 patients participating in the UK FSHD registry can be subdivided into 4 patterns of self-reported symptoms

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant incurable skeletal muscle disease. FSHD1 constitutes 95% of cases and is linked to truncation of the D4Z4 macrosatellite at 4q35. In most cases the condition initially presents with facial and proximal weakness of the upper limbs, but over the course of the disease involves lower limb and truncal muscles. Weakness is progressive and frequently asymmetric, which is a hallmark of the disease. Here we performed an analysis of 643 FSHD1 patients in the UK FSHD patient registry, investigating factors affecting rate of onset of 5 major FSHD symptoms: facial, periscapular, foot dorsiflexor, hip girdle weakness, and hearing loss. We found shorter D4Z4 repeat length associated with accelerated onset of each symptom. Furthermore, paternal inheritance of the pathogenic allele was associated with accelerated onset of foot dorsiflexor weakness, while pregnancy and carrying multiple children to term was associated with slower onset of all muscle symptoms. Lastly, we performed clustering analysis on age of onset of the 4 muscle symptoms across 222 patients. We identified 4 clinical presentations of FSHD1. A classical presentation (74%) and 3 facial sparing phenotypes: a mild presentation (5%) with later facial and periscapular involvement, an early shoulder presentation (10%) with accelerated periscapular weakness and an early foot presentation (9%) with accelerated foot dorsiflexor weakness. The mild presentation was associated with longer D4Z4 repeat lengths, while the early foot presentation had a female bias. We note, however that symptom progression differs significantly in these 4 clinical presentations independently of D4Z4 repeat length and gender, motivating investigation of further modifiers of FSHD1 severity.

Cardiac Intervention Improves Heart Disease and Clinical Outcomes in Patients With Muscular Dystrophy in a Multidisciplinary Care Setting

Background

Patients with muscular dystrophy (MD) represent a vulnerable patient population with no clearly defined care model in modern‐day clinical practice to manage a high burden of heart disease and comorbidities. We demonstrate the effectiveness of cardiac interventions, namely the initiation and optimization of medical and device therapies, as part of a multidisciplinary care approach to improve clinical outcomes in patients with MD.

Methods and Results

We conducted a prospective cohort study at the Neuromuscular Multidisciplinary clinic following patients with dystrophinopathies, limb‐girdle MD, type 1 myotonic dystrophy, and facioscapulohumeral MD. A negative control group classified as non‐MD myopathies without heart disease, was also tracked. Our cohort of 185 patients (median age: 42 years; 79 [42.7%] women), included 145 patients with MD. Cardiomyopathy was present in 65.6% of the patients with dystrophinopathies (21 of 32) and 27.3% of the patients with limb‐girdle MD (9 of 33). Conduction abnormalities were common in type 1 myotonic dystrophy (33.3% [20/60] patients). Cardiac intervention reversed systolic dysfunction, with left ventricular ejection fraction improving from 43% to 50.0% over a 3‐year period. A sustained reduction in healthcare utilization was also observed. The number of outpatient clinic visits decreased from 3.0 to 1.5 visits per year, the duration of hospitalizations was reduced from 14.2 to 0.9 days per year, and the number of cardiac‐related hospitalizations decreased from 0.4 to 0.1 hospitalizations per year associated with low mortality.

Conclusions

Our study demonstrates that cardiac intervention as part of a comprehensive multidisciplinary care approach to treating patients with MD leads to a sustained improvement in clinical outcomes.

[Inpatients with facioscapulohumeral muscular dystrophy in specialized institutions in Japan from 1999 to 2013-Clinical condition changes and causes of death]

We analyzed the registration data of inpatients with facioscapulohumeral muscular dystrophy (FSHD) receiving care at 27 specialized institutions for muscular dystrophy in Japan from 1999 to 2013 using data from October 1 of each year. The number of inpatients of each year ranged from 63 to 72 (67.1 ± 3.3) throughout the study period. Those aged over 50 years gradually increased during the study period, while the oldest inpatient was 82.8 years old. Most could not walk. The rate of respirator dependency increased from 21.0% in 1999 to 71.0% in 2013, while the rate of patients receiving oral nutrition was 98.4% in 1999 and then reduced to 75.4% in 2013. There were 36 death cases reported in the database, including 15 patients with respiratory failure and 4 with heart failure. Our findings indicate that FSHD patients in a severe condition are impacted by respiratory and nutritional problems and their prognosis for survival is related to respiratory failure.

Subclinical myocardial injury in patients with Facioscapulohumeral muscular dystrophy 1 and preserved ejection fraction - assessment by cardiovascular magnetic resonance

BACKGROUND

Facioscapulohumeral muscular dystrophy type 1 (FSHD1) is an autosomal dominant and the third most common inherited muscle disease. Cardiac involvement is currently described in several muscular dystrophies (MD), but there are conflicting reports in FSHD1. Mostly, FSHD1 is recognized as MD with infrequent cardiac involvement, but sudden cardiac deaths are reported in single cases. The aim of this study is to investigate whether subclinical cardiac involvement in FSHD1 patients is detectable in preserved left ventricular systolic function applying cardiovascular magnetic resonance (CMR).

METHODS

We prospectively included patients with genetically confirmed FSHD1 (n = 52, 48 ± 15 years) and compared them with 29 healthy age-matched controls using a 1.5 T CMR scanner. Myocardial tissue differentiation was performed qualitatively using focal fibrosis imaging (late gadolinium enhancement (LGE)), fat imaging (multi-echo sequence for fat/water-separation) and parametric T2- and T1-mapping for quantifying inflammation and diffuse fibrosis. Extracellular volume fraction was calculated. A 12-lead electrocardiogram and 24-h Holter were performed for the assessment of MD-specific Groh-criteria and arrhythmia.

RESULTS

Focal fibrosis by LGE was present in 13 patients (25%,10 men), fat infiltration in 7 patients (13%,5 men). T2 values did not differ between FSHD1 and healthy controls. Native T1 mapping revealed significantly higher values in patients (global native myocardial T1 values basal: FSHD1: 1012 ± 26 ms vs. controls: 985 ± 28 ms, p < 0.01, medial FSHD1: 994 ± 37 ms vs. controls: 982 ± 28 ms, p = 0.028). This was also evident in regions adjacent to focal fibrosis, indicating diffuse fibrosis. Groh-criteria were positive in 1 patient. In Holter, arrhythmic events were recorded in 10/43 subjects (23%).

CONCLUSIONS

Patients with FSHD1 and preserved left ventricular ejection fraction present focal and diffuse myocardial injury. Longitudinal multi-center trials are needed to define the impact of myocardial changes as well as a relation between myocardial injury and arrhythmias on long-term prognosis and therapeutic decision-making.

TRIAL REGISTRATION

ISRCTN registry with study ID ISRCTN13744381 .

Management strategies in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) also known as Landouzy-Dejerine disease, is an autosomal-dominant disorder of the skeletal muscles with the name according to the various muscle groups it affects: the face, shoulders and upper arms. It is the third most common genetic degenerative disorder of the skeletal muscles without specific patterns in all the affected individuals. At present there is no cure for the disease but numerous management strategies are available to improve the quality of life and prevent further degeneration of various muscle groups. This review aims to provide an insight on the management strategies for FSHD patients including both lifestyle and medical intervention.

Early onset as a marker for disease severity in facioscapulohumeral muscular dystrophy

OBJECTIVE

To assess the relation between age at onset and disease severity in facioscapulohumeral muscular dystrophy (FSHD).

METHODS

In this prospective cross-sectional study, we matched adult patients with FSHD with an early disease onset with 2 sex-matched FSHD control groups with a classic onset; the first group was age matched, and the second group was disease duration matched. Genetic characteristics, muscle performance, respiratory functioning, hearing loss, vision loss, epilepsy, educational level, and work status were compared with the 2 control groups.

RESULTS

Twenty-eight patients with early-onset FSHD were age (n = 28) or duration (n = 27) matched with classic-onset patients. Patients with early-onset FSHD had more severe muscle weakness (mean FSHD clinical score 11 vs 5 in the age-matched and 9 in the duration-matched group, p < 0.05) and a higher frequency of wheelchair dependency (57%, 0%, and 30%, respectively, p < 0.05). In addition, systemic features were more frequent in early-onset FSHD, most important, hearing loss, decreased respiratory function and spinal deformities. There was no difference in work status. Genetically, the shortest D4Z4 repeat arrays (2-3 units) were found exclusively in the early-onset group, and the largest repeat arrays (8-9 units) were found only in the classic-onset groups. De novo mutations were more frequent in early-onset patients (46% vs 4%).

CONCLUSIONS

Patients with early-onset FSHD more often have severe muscle weakness and systemic features. The disease severity is greater than in patients with classic-onset FSHD who are matched for disease duration, suggesting that the progression is faster in early-onset patients.

The French National Registry of patients with Facioscapulohumeral muscular dystrophy

Background

Facioscapulohumeral muscular dystrophy is a rare inherited neuromuscular disease with an estimated prevalence of 1/20,000 and France therefore harbors about 3000 FSHD patients. With research progress and the development of targeted therapies, patients’ identification through registries can facilitate and improve recruitment in clinical trials and studies.

Results

The French National Registry of FSHD patients was designed as a mixed model registry involving both patients and physicians, through self-report and clinical evaluation questionnaires respectively, to collect molecular and clinical data. Because of the limited number of patients, data quality is a major goal of the registry and various automatic data control features have been implemented in the bioinformatics system. In parallel, data are manually validated by molecular and clinical curators. Since its creation in 2013, data from 638 FSHD patients have been collected, representing about 21% of the French FSHD population. The mixed model strategy allowed to collect 59.1% of data from both patients and clinicians; 26 and 14.9% from respectively patients and clinicians only. With the identification of the FSHD1 and FSHD2 forms, specific questionnaires have been designed. Though FSHD2 patients are progressively included, FSHD1 patients still account for the majority (94.9%). The registry is compatible with the FAIR principles as data are Findable, Accessible and Interoperable. We thus used molecular standards and standardized clinical terms used by the FILNEMUS French network of reference centers for the diagnosis and follow-up of patients suffering from a rare neuromuscular disease. The implemented clinical terms mostly map to dictionaries and terminology systems such as SNOMED-CT (75% of terms), CTV3 (61.7%) and NCIt (53.3%). Because of the sensitive nature of data, they are not directly reusable and can only be accessed as aggregated data after evaluation and approval by the registry oversight committee.

Conclusions

The French National Registry of FSHD patients belongs to a national effort to develop databases, which should now interact with other initiatives to build a European and/or an international FSHD virtual registry for the benefits of patients. It is accessible at www.fshd.fr and various useful information, links, and documents, including a video, are available for patients and professionals.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0960-x) contains supplementary material, which is available to authorized users.

Isokinetic assessment of trunk muscles in facioscapulohumeral muscular dystrophy type 1 patients

Facioscapulohumeral muscular dystrophy type 1 is the third most common inherited myopathy. Its severity is proportionate to the loss of microsatellite D4Z4 repetitions, which are below 10. Patients suffer from weakness in facial muscles, shoulder girdles and ankle dorsiflexors. Trunk impairment is reported in few studies. To assess correlation between D4Z4 number of repetitions in facioscapulohumeral muscular dystrophy type 1 patients and trunk extensors and flexors isokinetic peak torque, 48 patients with southern Blot confirmed facioscapulohumeral muscular dystrophy type 1 were enrolled to perform clinical evaluation (Ricci's Clinical Severity Scoring, Berg Balance Scale, Functional Reach Test, timed up-and-go test, six-minute walk test, functional independence measure) and trunk isokinetic assessment. Trunk extensors and flexors isokinetic peak torque at 60°/sec were significantly correlated with number of D4Z4 microsatellite repetitions, sex, weight and age-independent (r = 0.391 [0.121; 0.662], p < 0.006 and r = 0.334 [0.028; 0.641], p < 0.033, respectively). Ricci's Clinical Severity Scoring was significantly correlated to trunk extensors isokinetic peak torque at 60°/sec, sex and weight-independent (r = -0.743 [-0.938; -0.548], p < 0.0001). This study demonstrates moderate correlation between pathologic compression of D4Z4 microsatellite array and trunk extensors isokinetic strength among facioscapulohumeral muscular dystrophy type I patients.

Cardiac Abnormalities in Type 1 Facioscapulohumeral Muscular Dystrophy

OBJECTIVES

We conducted a retrospective study to characterize the cardiac complications in patients with genetically confirmed type 1 facioscapulohumeral dystrophy.

METHODS

We reviewed baseline cardiac investigations, including electrocardiogram, Holter electrocardiogram and echocardiogram, as well as cardiac complications that occurred during follow-up in 56 adult patients (37 men, mean duration of disease: 20 years).

RESULTS

Baseline evaluation revealed minor cardiac anomalies in 23 patients including incomplete right bundle branch block (iRBBB) in 13 patients (23%). Over a mean follow-up period of 7.2 years, there was no cardiac death, no patient developed cardiomyopathy, and 28 patients (50%) experienced cardiac anomalies. Among these patients, 3 had one or more major events (heart failure and/or atrial fibrillation). The remaining 25 patients presented minor cardiac anomalies of which iRBBB was the most frequent (25%).

CONCLUSIONS

Cardiac anomalies identified during the follow-up of patients with type 1 facioscapulohumeral dystrophy are mainly minor anomalies, dominated by the iRBBB.

Early onset facioscapulohumeral dystrophy - a systematic review using individual patient data

Infantile or early onset is estimated to occur in around 10% of all facioscapulohumeral dystrophy (FSHD) patients. Although small series of early onset FSHD patients have been reported, comprehensive data on the clinical phenotype is missing. We performed a systematic literature search on the clinical features of early onset FSHD comprising a total of 43 articles with individual data on 227 patients. Additional data from four cohorts was provided by the authors. Mean age at reporting was 18.8 years, and 40% of patients were wheelchair-dependent at that age. Half of the patients had systemic features, including hearing loss (40%), retinal abnormalities (37%) and developmental delay (8%). We found an inverse correlation between repeat size and disease severity, similar to adult-onset FSHD. De novo FSHD1 mutations were more prevalent than in adult-onset FSHD. Compared to adult FSHD, our findings indicate that early onset FSHD is overall characterized by a more severe muscle phenotype and a higher prevalence of systemic features. However, similar as in adults, a significant clinical heterogeneity was observed. Based on this, we consider early onset FSHD to be on the severe end of the FSHD disease spectrum. We found natural history studies and treatment studies to be very scarce in early onset FSHD, therefore longitudinal studies are needed to improve prognostication, clinical management and trial-readiness.

Facioscapulohumeral Muscular Dystrophy

PURPOSE OF REVIEW

This article describes the clinical characteristics, diagnosis, molecular pathogenesis, and treatment of facioscapulohumeral muscular dystrophy (FSHD).

RECENT FINDINGS

FSHD comprises two genetically distinct types that converge on a common downstream pathway of the expression of the toxic protein DUX4. Approximately 95% of patients have FSHD type 1 (FSHD1), in which loss of DNA repetitive elements (D4Z4 repeats) in the subtelomeric region of chromosome 4q causes decreased methylation and epigenetic derepression of DUX4, a gene contained within each D4Z4 repeat. FSHD type 2 (FSHD2) occurs through a deletion-independent mechanism but, similar to FSHD1, leads to decreased methylation and epigenetic derepression in the same region of chromosome 4q. Whereas FSHD1 is dominantly inherited, FSHD2 shows digenic inheritance, and about 80% of patients will have a mutation in the SMCHD1 gene. DUX4 lacks a polyadenylation signal, so both FSHD1 and FSHD2 only occur in the presence of permissive 4q polymorphisms, which provide a stabilizing polyadenylation sequence. FSHD is an epigenetic disease, and penetrance and severity are related to both the number of residual D4Z4 units and D4Z4 methylation.

SUMMARY

Recent consensus guidelines outline standards for care for FSHD, and identification of potential therapeutic targets have shifted emphasis in the research community toward drug development and clinical trial planning.

Unusual scapular winging - A case report

Scapular mobility has a central role in maintaining normal upper limb function. Scapular winging is characterized by a failure in the dynamic stabilization of the scapula against the thoracic wall resulting in a condition in which the medial border of the scapula is prominent. The following case describes a patient who was referred to physiotherapy due to abnormal scapular protrusion. The main findings of the physical examination showed weakness of the scapular stabilizers more prominent on the right side than of the left. Additionally, the physical examination demonstrated weakness of the abdominal muscles, hip adductors, and ankle dorsi-flexors, as well as some facial muscles. The electromyography results were inconclusive. Further examination led to clinical suspicion of Facioscapulohumeral Dystrophy (FSHD) as a diagnosis, which was confirmed by genetic testing. Facioscapulohumeral Dystrophy is characterized by symptoms related to motor function and in most cases becomes evident in patients in their 20s and 30s. The disease signs and symptoms are often identified in a clinical setting. Currently, there are no reports describing an effective treatment for the disease. However, physiotherapy, moderate physical exercise, counselling, and use of suitable aids and orthoses may help improve functionality and mobility. This case report aims to increase the awareness of musculoskeletal physiotherapists to this unique dystrophy, when encountering complex presentations with scapular winging.

Intermittent pre-excitation-syndrome in facio-scapulo-humeral muscular dystrophy

Pre-excitation-syndrome has not been reported as a phenotypic feature of facio-scapulo-humeral muscular dystrophy (FSH-MD). In a 39-year-old male with FSH-MD due to a reduced tandem repeat size in the D4Z4-locus on chromosome 4q35, cardiac involvement, manifesting as an incomplete right bundle-branch-block, tall T-waves in V 3-5, ST-elevation in V 2-4, and mild thickening of the left ventricular myocardium, was first recognised 10 years earlier. Follow-up at age 39 years revealed mild myocardial thickening, two intra-ventricular aberrant bands, and, surprisingly, intermittent pre-excitation on a routine electrocardiography. Cardiac involvement in FSH-MD may manifest as hypertrophic cardiomyopathy or various arrhythmias, of which one may be pre-excitation-syndrome.

Facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is characterized by a typical and asymmetric pattern of muscle involvement and disease progression. Two forms of FSHD, FSHD1 and FSHD2, have been identified displaying identical clinical phenotype but different genetic and epigenetic basis. Autosomal dominant FSHD1 (95% of patients) is characterized by chromatin relaxation induced by pathogenic contraction of a macrosatellite repeat called D4Z4 located on the 4q subtelomere (FSHD1 patients harbor 1 to 10 D4Z4 repeated units). Chromatin relaxation is associated with inappropriate expression of DUX4, a retrogene, which in muscles induces apoptosis and inflammation. Consistent with this hypothesis, individuals carrying zero repeat on chromosome 4 do not develop FSHD1. Not all D4Z4 contracted alleles cause FSHD. Distal to the last D4Z4 unit, a polymorphic site with two allelic variants has been identified: 4qA and 4qB. 4qA is in cis with a functional polyadenylation consensus site. Only contractions on 4qA alleles are pathogenic because the DUX4 transcript is polyadenylated and translated into stable protein. FSHD2 is instead a digenic disease. Chromatin relaxation of the D4Z4 locus is caused by heterozygous mutations in the SMCHD1 gene encoding a protein essential for chromatin condensation. These patients also harbor at least one 4qA allele in order to express stable DUX4 transcripts. FSHD1 and FSHD2 may have an additive effect: patients harboring D4Z4 contraction and SMCHD1 mutations display a more severe clinical phenotype than with either defect alone. Knowledge of the complex genetic and epigenetic defects causing these diseases is essential in view of designing novel therapeutic strategies. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.

Arrhythmias in the muscular dystrophies

The muscular dystrophies are a group of inherited diseases affecting skeletal muscle that also affect cardiac muscle. Cardiac involvement occurs as a degenerative process with fibrosis and fatty replacement of the myocardium. Electrophysiologists are asked to participate in the care of muscular dystrophy patients because of the risk of atrial arrhythmias, conduction disease, bradycardia, ventricular arrhythmias, and sudden death. Duchenne, Becker, and limb-girdle types 2C-2F and 2I are muscular dystrophies in which the development of a dilated cardiomyopathy is common. Arrhythmias and conduction disease occur after the development of the dilated cardiomyopathy. Patients are considered for pacemakers or implantable cardioverter-defibrillators on the basis of guidelines used for nonischemic cardiomyopathies. Myotonic types 1 and 2, Emery-Dreifuss, limb-girdle type 1B, and facioscapulohumeral muscular dystrophies present with conduction disease and associated arrhythmias and variably with a dilated cardiomyopathy. In myotonic type 1, Emery-Dreifuss, and limb-girdle type 1B muscular dystrophies, conduction abnormalities are frequent and often require pacing. Recent studies support the use of prophylactic implantable cardioverter-defibrillators rather than pacemakers. In all the muscular dystrophies, respiratory muscle involvement can impact quality and quantity of life and needs to be factored in when considering a prophylactic device.

In junk we trust: repetitive DNA, epigenetics and facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant myopathy with a peculiar etiology. Unlike most genetic disorders, FSHD is not caused by mutations in a protein-coding gene. Instead, it is associated with contraction of the D4Z4 macrosatellite repeat array located at 4q35. Interestingly, D4Z4 deletion is not sufficient per se to cause FSHD. Moreover, the disease severity, its rate of progression and the distribution of muscle weakness display great variability even among close family relatives. Hence, additional genetic and epigenetic events appear to be required for FSHD pathogenesis. Indeed, recent findings suggest that virtually all levels of epigenetic regulation, from DNA methylation to higher order chromosomal architecture, exhibit alterations in the disease locus causing deregulation of 4q35 gene expression, ultimately leading to FSHD.

Atypical onset in a series of 122 cases with FacioScapuloHumeral Muscular Dystrophy

INTRODUCTION

FacioScapuloHumeral Muscular Dystrophy (FSHD), a disease linked to a heterozygous D4Z4 deletion on chromosome 4q35, typically starts with shoulder-girdle and facial muscle involvement. Atypical presentations have occasionally been reported, but their frequency has still not been defined.

PATIENTS AND METHODS

We studied the occurrence rate of FSHD with atypical onset in 122 symptomatic subjects from 76 unrelated families with genetically confirmed FSHD. These 75 males and 47 females, with a mean age of 49 years (range: 11-85), had a mean EcoRI fragment of 25 kb (range: 11-38).

RESULTS

Typical shoulder-girdle or facial weakness at onset was reported by 88 patients (72%). Unusual presentations included: foot drop in 16 (13%) and proximal lower limb weakness in eight patients (7%). Two cases at onset manifested quite atypical, apparently non-FSHD-related syndromes: a 42-year-old woman presented with infantile epilepsy and a 41-year-old man with myoglobinuria. In the latter patient, DNA analysis detected a 4q35 deletion associated to an heterozygous CAPN3 mutation.

CONCLUSION

FSHD presentation with foot drop or lower limb proximal weakness appeared to be more frequent than expected. This type of weakness at onset has to be considered premature, but still representative of disease-related muscle involvement. Quite atypical onset appears very rare and calls for further investigation on non-FSHD-related etiology.

[Facioscapulohumeral muscular dystrophy. Clinical picture, atypical forms, diagnostics, genetics]

The classic phenotype of the facioscapulohumeral muscular dystrophy (FSHD) includes an initially restricted pattern of asymmetric weakness of facial and shoulder girdle muscles. Disease progression is usually slow and typically accompanied by foot extensor muscle weakness and pelvic girdle weakness. Atypical patterns of FSHD that include isolated camptocormia and facial muscle sparing exceed current diagnostic criteria. No causal genetic lesion in FSHD has been identified yet. In the vast majority of cases, FSHD results from a heterozygous partial deletion of a critical number of repetitive elements (D4Z4) on chromosome 4q35 (4qA allele). Molecular diagnostic testing is appropriate to confirm the diagnosis of FSHD without need for muscle biopsy. Penetrance of this dominantly inherited disorder is high, exhibiting a great phenotypic variability in clinical pattern and disease progression even among affected members of the same family.

Genetics of heart failure and sudden death

Since the sentinel discovery of long QT syndrome as a channelopathy in 1995, many significant strides have been made related to exposing the pathogenic mechanisms underlying sudden cardiac death. However, elucidating the most influential genetic and environmental determinants that underlie the variable penetrance and expressivity of the primary syndrome-associated mutation remains a daunting task.

Facioscapulohumeral dystrophy and scapuloperoneal syndromes

Facioscapulohumeral dystrophy (FSHD) is the third most common muscular dystrophy. It is named for its characteristic involvement of the muscles of the face and upper arm. It is present worldwide, with a prevalence of around 4 per 100000 and an incidence of about 1 in 20000. Overall lifespan is not affected significantly. The scapuloperoneal syndrome is a rarer presentation that may cause some confusion. FSHD is an autosomal dominant condition. The molecular genetics of FSHD are complex, with current understanding focusing on epigenetic effects related to contraction-dependent (FSHD1) and contraction-independent (FSHD2) effects of a hypomethylated repeat sequence (D4Z4), in the presence of a specific 4qA161 phenotype. Molecular genetic diagnosis is available based on these findings, but with some complexities which may lead to false-negative results on routine laboratory investigation. No medication has been demonstrated to alter the clinical course of the disease significantly. A range of supportive measures may be applied. This chapter reviews the epidemiology, pathogenesis, genetics, clinical features, investigation, prognosis, and management of patients with FSHD and the scapuloperoneal syndrome.

The cell biology of disease: FSHD: copy number variations on the theme of muscular dystrophy

In humans, copy number variations (CNVs) are a common source of phenotypic diversity and disease susceptibility. Facioscapulohumeral muscular dystrophy (FSHD) is an important genetic disease caused by CNVs. It is an autosomal-dominant myopathy caused by a reduction in the copy number of the D4Z4 macrosatellite repeat located at chromosome 4q35. Interestingly, the reduction of D4Z4 copy number is not sufficient by itself to cause FSHD. A number of epigenetic events appear to affect the severity of the disease, its rate of progression, and the distribution of muscle weakness. Indeed, recent findings suggest that virtually all levels of epigenetic regulation, from DNA methylation to higher order chromosomal architecture, are altered at the disease locus, causing the de-regulation of 4q35 gene expression and ultimately FSHD.

Facioscapulohumeral muscular dystrophy: epidemiological and molecular study in a north-east Italian population sample

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease associated with a partial deletion on chromosome 4q35. Few relevant investigations have been reported on its epidemiology and were essentially based on clinical diagnosis, having been performed before recognition of the molecular mutation. We report an epidemiological survey on FSHD patients, in which the diagnosis was obtained by combined clinical and molecular evaluation. The survey concerned the north-east Italian province of Padova, an area of 871,190 inhabitants (1 January 2004). We identified 40 patients affected by FSHD based on clinical diagnosis. In 33 of them, the EcoRI fragment size in the 4q35 region ranged from 14 to 35 kb. Four other patients belonging to the same family harbored a 38-kb fragment. In these four cases, the relationship between the borderline deletion with the mild FSHD phenotype was corroborated by additional haplotype reconstruction and segregation analysis. Interestingly, the same mild facial-sparing clinical pattern was apparent only in one other patient with an EcoRI fragment of 32 kb, suggesting that this unusual FSHD phenotype may be due to very small 4q35 deletions. On the whole, estimating a prevalence rate of 44 x 10(-6), our survey confirmed FSHD as one of the most frequent neuromuscular disorders in Western populations.

Primary myopathies and the heart

Myopathies are frequently not confined to the skeletal muscles but also involve other organs or tissues. One of the most frequently affected organ in addition to the skeletal muscle is the heart (cardiac involvement, CI). CI manifests as impulse generation or conduction defects, focal or diffuse myocardial thickening, dilation of the cardiac cavities, relaxation abnormality, hypertrophic, dilated, restrictive cardiomyopathy, apical form of hypertrophic cardiomyopathy, noncompaction, Takotsubo phenomenon, secondary valve insufficiency, intra-cardiac thrombus formation, or heart failure with systolic or diastolic dysfunction. CI occurs in dystrophinopathies, Emery-Dreifuss muscular dystrophy, facioscapulohumeral muscular dystrophy, limb girdle muscular dystrophies, laminopathies, congenital muscular dystrophies, myotonic dystrophies, congenital myopathies, metabolic myopathies, desminopathies, myofibrillar myopathy, Barth syndrome, McLeod syndrome, Senger's syndrome, and Bethlem myopathy. Patients with myopathy should be cardiologically investigated as soon as their neurological diagnosis is established, since supportive cardiac therapy is available, which markedly influences prognosis and outcome of CI in these patients.

Facioscapulohumeral dystrophy

Facioscapulohumeral dystrophy (FSHD) is the third most common inherited muscular dystrophy after Duchenne dystrophy and myotonic dystrophy. Over the last decade, major advances have occurred in the understanding of the genetics of this disorder. Despite these advances, the exact mechanisms that lead to atrophy and weakness secondary to the genetic defect are still not understood. The purposes of this article are to increase awareness of FSHD among clinicians; to provide an update regarding the genetics, clinical features, natural history, and current management of FSHD; and to discuss opportunities for research.

Facioscapulohumeral muscular dystrophy: a multicenter study on hearing function

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant progressive myopathy, characteristically associated with a 4q35 deletion. In the unusual infantile-onset form of this degenerative disease, sensorineural hearing loss is a frequent clinical manifestation, whereas in patients with typical late-onset FSHD, investigations regarding hearing impairment yielded controversial results. We describe the findings of a multicenter investigation on possible auditory impairment in a series of 73 FSHD patients with a genetically confirmed diagnosis. Among them, 49 cases with no risk factors for deafness, aside from the disease, were identified by a clinical questionnaire and otoscopic examination (mean age 37.8 years, 31 males and 18 females). These subjects were evaluated by pure-tone audiometry. None were aware of hearing loss, while 4 had raised unilateral or bilateral pure-tone audiometric thresholds at 4000 and 8000 Hz, when evaluated by standardized tables. However, the mean raw pure-tone audiometric threshold values for these 49 cases were not significantly different from those of 55 controls (mean age 37.1 years, 32 males and 23 females). Moreover, by statistical analysis, age of onset, degree of muscular weakness and 4q35 EcoRI fragment size made no significant difference to auditory thresholds in our FSHD patients. Overall, the results of our multicenter study suggest that hearing loss in typical FSHD is not more prevalent than in the normal population.