Motor Outcomes to Validate Evaluations in Pediatric FSHD (MOVE Peds)

MOVE Peds is a prospective 2-year study recruiting eighty pediatric participants to accelerate therapeutic development for pediatric-onset FSHD. The study aims to validate outcomes and refine clinical trial strategies. Previous cross-sectional studies suggest that younger age of onset is linked to greater clinical severity and that having 1-3 D4Z4 repeats is associated with extra-muscular complications in pediatric FSHD. Prospective studies in early-onset FSHD have been limited by the small number of sites and low recruitment and follow-up rates. Early-onset pediatric FSHD is of high interest to drug companies because: 1. It results in a more significant disease burden than in adults. 2. Treating FSHD at earlier ages may have a more lasting and profound effect. 3. Genetic, molecular, and clinical factors may differ between pediatric and adult-onset FSHD. 4. Smaller body size and faster progression rates may make AAV-delivered gene therapies more feasible. The FSHD CTRN's previous research showed that the FSHD composite functional measure (FSHD-COM), reachable workspace (RWS), and quantitative MRI measures (qMRI) are responsive to disease progression or treatment in adults with FSHD and correlate with performance. Investigators hypothesize that early changes in qMRI in pediatric subjects will predict 2-year changes in FSHD-COM Peds or RWS.