We studied the experimental mirror-difference charge radii of 11B-11C, 13C-13N, 15N-15O, 17N-17Ne pairs for the first time. We find that the 

values of 13C-13N and 15N-15O pairs follow well the empirical relation to the isospin asymmetry predicted by the ab-inito calculations, while 

 of 11B-11C and 17N-17Ne pairs deviate from such relation by more than two standard deviations, which points out the role of charge-symmetry breaking.