ACTA1 and facioscapulohumeral muscular dystrophy: Analysis of the gastrocnemius muscle from chronic FSHD-like mice revealed that the leukocyte CD45+ population was enriched by 3- and 2-fold in 6 and 14–18 month-old ACTA1-MCM/FLExD/+ muscles, respectively, when compared to ACTA1-MCM/+ age-matched controls (Fig. 4B).