Notably, the median serum CK/Cr ratio in the DMD group was approximately 3.7 times that in the BMD group, whereas the serum titin/Cr ratio in the DMD group was approximately 10-fold higher than that in the BMD group (d = 0.74, 95% CI 0.25–1.22). Here, TTN is linked to Duchenne muscular dystrophy.