Muscle ultrasound is a responsive biomarker in facioscapulohumeral dystrophy.

OBJECTIVE

With drug trials starting soon, responsive, relevant, and patient-friendly biomarkers are highly needed in facioscapulohumeral dystrophy (FSHD). Our objective was to assess muscle ultrasound (MUS) as an imaging biomarker in patients with FSHD.

METHODS

One-year observational, longitudinal study of both quantitative and qualitative MUS changes in FSHD.

RESULTS

Twenty-two patients with symptomatic FSHD1 underwent a clinical examination and MUS at baseline and after 1-year follow-up. The qualitative MUS sum score increased from 18.59 to 20.32 ( = 0.005) and the quantitative MUS sum scores increased from 19.96 to 24.72 ( = 0.003). The clinical scores did not change over 1 year. Muscle echogenicity correlated with the FSHD clinical score at baseline ( = 0.61, = 0.002).

CONCLUSIONS

MUS shows a significant increase in echogenicity in FSHD over 1 year. Both quantitative and qualitative MUS correlate cross-sectionally with clinical severity in FSHD and identify structural muscle changes in a clinically stable group of patients. MUS thus seems a potentially responsive biomarker that could be standardized between centers. We recommend its use in therapeutic trials.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that in patents with FSHD1, MUS findings correlate with baseline FSHD clinical scores.