Natural history of limb girdle muscular dystrophy R1 (LGMDR1): a GRASP consortium study

Identifying clinical outcome assessments (COAs) that are able to detect change in functional abilities over time in the limb girdle muscular dystrophy (LGMD) population is critical for managing disease progression in addition to determining drug efficacy in the context of anticipated therapeutic trials. Through the Genetic Resolution and Assessments Solving Phenotypes in LGMD (GRASP-LGMD) Consortium, 42 participants with LGMDR1 were enrolled in a 12-month natural history study across 11 international sites. Each participant completed a battery of COAs, including the North Star Assessment for Limb Girdle-Type Muscular Dystrophies (NSAD), 100-meter timed test (100 m), Performance of the Upper Limb (PUL), and 4-Stair Climb (4SC) in addition to several patient-reported outcome measures (PROM) across three time points in this year-long study. Participants with LGMDR1 demonstrate significant decline in the 100 m, NSAD, PUL, and 4SC over a 12-month time period. The rate of decline was greater in those considered to be higher functioning (10-meter time <12 s) while genetic variant types did not appear to significantly influence the rate of decline in our cohort. A combination of COAs is determined to be the best approach at measuring functional change over time in patients with LGMDR1.