Muscle pathology grade for facioscapulohumeral muscular dystrophy biopsies

Abstract

Background As we move towards planning for clinical trials in Facioscapulohumeral Muscular Dystrophy (FSHD), a better understanding of the clinical relationship with morphological changes in FSHD muscle biopsies will be important for stratifying patients and understanding post-therapeutic changes in muscle. Methods We performed a prospective cross-sectional study of quadriceps muscle biopsies in 74 genetically confirmed FSHD participants (64 FSHD1, 10 FSHD2). We compared a 12-point muscle pathology grade to genetic mutation, disease severity score, and quantitative myometry. Results Pathology grade had moderate correlations with genetic mutation (rho=−0.45, P<0.001), clinical severity score (rho=0.53, P<0.001), disease duration (rho=0.31, P=0.03), and quantitative myometry (rho=−0.47, P<0.001). We found no difference in the frequency of inflammation between FSHD types 1 and 2. Conclusions The pathology grade of quadriceps muscle may be a useful marker of disease activity in FSHD, and it may have a role in stratification for future clinical trials.

Clinical and genetic features of patients with facial‐sparing facioscapulohumeral muscular dystrophy

“…Besides, our SHD patients had progressive limb weakness and muscle atrophy without facial involvement during follow-up, relatively excluded from pre-symptomatic states. The biopsies exhibited non-specific and mild myopathic changes including a small amount of inflammatory infiltration, consistent with the previous report in classical FSHD [18]. Extramuscular assessments covering pulmonary function and electrocardiogram were normal or mild.…”

Myositis Mimics

“…Muscle biopsy typically demonstrates nonspecific myopathic changes, including fiber size variability, internalized nuclei, and fibrosis. Up to one third of patients have an inflammatory infiltrate composed of both CD4+ and CD8+ T cells that can lead to misdiagnosis as PM [42,43]. The infiltrate, which may be most prevalent in the early stages of the disease, appears patchy and varies widely in intensity between biopsy samples [44].…”

Electrical impedance myography in facioscapulohumeral muscular dystrophy: A 1‐year follow‐up study

“…In FSHD, muscles undergo structural changes as the disease progresses, including atrophy, fatty infiltration, edema, and fibrosis. These changes can all influence the impedance across the muscle tissue . In a previous cross‐sectional study on EIM in FSHD, we showed that EIM is a reliable measure of muscle composition in FSHD that correlates with functional outcome measures .…”

“…These changes can all influence the impedance across the muscle tissue. 8,9 In a previous cross-sectional study on EIM in FSHD, we showed that EIM is a reliable measure of muscle composition in FSHD that correlates with functional outcome measures. 10 Studies on other neuromuscular disorders such as amyotrophic lateral sclerosis, congenital myopathies, and Duchenne muscular dystrophy have shown that EIM is able to capture changes over time, [11][12][13][14] although research is ongoing regarding what variables are most suitable to use in each different disorder.…”