Reduced specific force in patients with mild and severe facioscapulohumeral muscular dystrophy

Saskia Lassche*, Nicol C. Voermans, Tim Schreuder, Arend Heerschap, Benno Küsters, Coen A. C. Ottenheijm, Maria T. E. Hopman, Baziel G. M. van Engelen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: Specific force, that is the amount of force generated per unit of muscle tissue, is reduced in patients with facioscapulohumeral muscular dystrophy (FSHD). The causes of reduced specific force and its relation with FSHD disease severity are unknown. Methods: Quantitative muscle magnetic resonance imaging (MRI), measurement of voluntary maximum force generation and quadriceps force-frequency relationship, and vastus lateralis muscle biopsies were performed in 12 genetically confirmed patients with FSHD and 12 controls. Results: Specific force was reduced by ~33% in all FSHD patients independent of disease severity. Quadriceps force-frequency relationship shifted to the right in severe FSHD compared to controls. Fiber type distribution in vastus lateralis muscle biopsies did not differ between groups. Conclusions: Reduced quadriceps specific force is present in all FSHD patients regardless of disease severity or fatty infiltration. Early myopathic changes, including fibrosis, and non-muscle factors, such as physical fatigue and musculoskeletal pain, may contribute to reduced specific force.
Original languageEnglish
JournalMuscle and Nerve
DOIs
Publication statusE-pub ahead of print - 2020

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