In alignment with functional analysis (Fig. S3C), overexpression of multiple cathepsins (CTSA, CTSB, CTSC, CTSD, CTSK, CTSS, CTSZ) and lysosomal membrane proteins (LAMP1, LAPTM5) in the myositis cluster strongly indicated active lysosomal function, suggesting a dynamic turnover of damaged or inflamed myofibers52,53. Here, CTSC is linked to myositis disease.