Muscle biopsies are used in clinical trials to measure target engagement of the investigational product. With many upcoming therapies for patients with facioscapulohumeral dystrophy (FSHD), the... Show moreMuscle biopsies are used in clinical trials to measure target engagement of the investigational product. With many upcoming therapies for patients with facioscapulohumeral dystrophy (FSHD), the frequency of biopsies in FSHD patients is expected to increase. Muscle biopsies were performed either in the outpatient clinic using a Bergström needle (BN-biopsy) or in a Magnetic Resonance Imaging machine (MRI-biopsy). This study assessed the FSHD patients’ experience of biopsies using a customized questionnaire. The questionnaire was sent to all FSHD patients who had undergone a needle muscle biopsy for research purposes, inquiring about biopsy characteristics and burden, and willingness to undergo a subsequent biopsy. Forty-nine of 56 invited patients (88%) completed the questionnaire, reporting on 91 biopsies. The median pain score (scale 0-10) during the procedure was 5 [2-8], reducing to 3 [1-5] and 2 [1-3] after one and 24 h, respectively. Twelve biopsies (13.2%) resulted in complications, eleven resolved within 30 days. BN-biopsies were less painful compared to MRI-biopsies (median NRS: 4 [2-6] vs. 7 [3-9], p = 0.001). The burden of needle muscle biopsies in a research setting is considerate and should not be underestimated. MRI-biopsies have a higher burden compared to BN-biopsies. Show less
Heuvel, A. van den; Lassche, S.; Mul, K.; Greco, A.; Granado, D.S.; Heerschap, A.; ... ; Maarel, S.M. van der 2022
With several therapeutic strategies for facioscapulohumeral muscular dystrophy (FSHD) entering clinical testing, outcome measures are becoming increasingly important. Considering the spatiotemporal... Show moreWith several therapeutic strategies for facioscapulohumeral muscular dystrophy (FSHD) entering clinical testing, outcome measures are becoming increasingly important. Considering the spatiotemporal nature of FSHD disease activity, clinical trials would benefit from non-invasive imaging-based biomarkers that can predict FSHD-associated transcriptome changes. This study investigated two FSHD-associated transcriptome signatures (DUX4 and PAX7 signatures) in FSHD skeletal muscle biopsies, and tested their correlation with a variety of disease-associated factors, including Ricci clinical severity score, disease duration, D4Z4 repeat size, muscle pathology scorings and functional outcome measures. It establishes that DUX4 and PAX7 signatures both show a sporadic expression pattern in FSHD-affected biopsies, possibly marking different stages of disease. This study analyzed two imaging-based biomarkers-Turbo Inversion Recovery Magnitude (TIRM) hyperintensity and fat fraction-and provides insights into their predictive power as non-invasive biomarkers for FSHD signature detection in clinical trials. Further insights in the heterogeneity of-and correlation between-imaging biomarkers and molecular biomarkers, as provided in this study, will provide important guidance to clinical trial design in FSHD. Finally, this study investigated the role of infiltrating non-muscle cell types in FSHD signature expression and detected potential distinct roles for two fibro-adipogenic progenitor subtypes in FSHD. Show less
Facioscapulohumeral muscular dystrophy (FSHD) is the second most common genetic myopathy, characterized by slowly progressing and highly heterogeneous muscle wasting with a typical onset in the... Show moreFacioscapulohumeral muscular dystrophy (FSHD) is the second most common genetic myopathy, characterized by slowly progressing and highly heterogeneous muscle wasting with a typical onset in the late teens/early adulthood [1]. Although the etiology of the disease for both FSHD type 1 and type 2 has been attributed to gain-of-toxic function stemming from aberrant DUX4 expression, the exact pathogenic mechanisms involved in muscle wasting have yet to be elucidated [2-4]. The 2021 FSHD International Research Congress, held virtually on June 24-25, convened over 350 researchers and clinicians to share the most recent advances in the understanding of the disease mechanism, discuss the proliferation of interventional strategies and refinement of clinical outcome measures, including results from the ReDUX4 trial, a phase 2b clinical trial of losmapimod in FSHD [NCT04003974]. Show less
Vincenten, S.C.C.; Stoep, N. van der; Paulussen, A.D.C.; Mul, K.; Badrising, U.A.; Kriek, M.; ... ; Lassche, S. 2021
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... Show moreReproductive 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. Show less
Greco, A.; Straasheijm, K.R.; Mul, K.; Heuvel, A. van den; Maarel, S.M. van der; Joosten, L.A.B.; ... ; Pruijn, G.J.M. 2021
Background: FSHD is caused by specific genetic mutations resulting in activation of the Double Homeobox 4 gene (DUX4). DUX4 targets hundreds of downstream genes eventually leading to muscle atrophy... Show moreBackground: FSHD is caused by specific genetic mutations resulting in activation of the Double Homeobox 4 gene (DUX4). DUX4 targets hundreds of downstream genes eventually leading to muscle atrophy, oxidative stress, abnormal myogenesis, and muscle inflammation. We hypothesized that DUX4-induced aberrant expression of genes triggers a sustained autoimmune response against skeletal muscle cells.Objective: This study aimed at the identification of autoantibodies directed against muscle antigens in FSHD. Moreover, a possible relationship between serum antibody reactivity and DUX4 expression was also investigated.Methods: FSHD sera (N=138, 48 +/- 16 years, 48% male) and healthy control sera (N=20, 47 +/- 14 years, 50% male) were analyzed by immunoblotting for antibodies against several skeletal muscle protein extracts: healthy muscle, FSHD muscle, healthy and FSHD myotubes, and inducible DUX4 expressing myoblasts. In addition, DUX4 expressing myoblasts were analyzed by immunofluorescence with FSHD and healthy control sera.Results: The results showed that the reactivity of FSHD sera did not significantly differ from that of healthy controls, with all the tested muscle antigen extracts. Besides, the immunofluorescent staining of DUX4-expressing myoblasts was not different when incubated with either FSHD or healthy control sera.Conclusion: Since the methodology used did not lead to the identification of disease-specific autoantibodies in the FSHD cohort, we suggest that autoantibody-mediated pathology may not be an important disease mechanism in FSHD. Nevertheless, it is crucial to further unravel if and which role the immune system plays in FSHD pathogenesis. Other innate as well as adaptive immune players could be involved in the complex DUX4 cascade of events and could become appealing druggable targets. Show less
Signorelli, M.; Mason, A.G.; Mul, K.; Evangelista, T.; Mei, H.; Voermans, N.; ... ; Spitali, P. 2020
Facioscapulohumeral muscular dystrophy (FSHD) is caused by the expression of DUX4 in skeletal muscles. A number of therapeutic approaches are being developed to antagonize the events preceding and... Show moreFacioscapulohumeral muscular dystrophy (FSHD) is caused by the expression of DUX4 in skeletal muscles. A number of therapeutic approaches are being developed to antagonize the events preceding and following DUX4 expression that leads to muscular dystrophy. Currently, the possibility to evaluate treatment response in clinical trials is hampered by the lack of objective molecular biomarkers connecting the disease cause to clinical performance. In this study we employed RNA-seq to examine gene expression in PAXgene tubes obtained from two independent cohorts of FSHD patients. Analysis of gene expression profiles did not lead to the identification of genes or pathways differentially expressed in FSHD patients, or associated with disease severity. In particular, we did not find evidence that the DUX4 and PAX7 signatures were differentially expressed. On the other hand, we were able to improve patient classification by including single genes or groups of genes in classification models. The best classifier was ROPN1L, a gene known to be expressed in testis, coincidentally the typical location of DUX4 expression. These improvements in patient classification hold the potential to enrich the FSHD clinical trial toolbox. Show less
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... Show moreObjective 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. Show less
