Radial acceleration relation for the Coma cluster UDGs (magenta error bars) together with that obtained for SPARC local spiral galaxies by McGaugh et al. (2016, blue colour scale, red squares, and dashed lines for the binned mean and standard deviation) and for dSphs of the Local Group (Lelli et al. 2017, light grey error bars for their least reliable data and dark grey error bars for their better quality sample). The plain black line shows the fit using Eq. (6) obtained by McGaugh et al. (2016) on the SPARC sample of spiral galaxies. The Coma cluster UDGs fall within the scatter obtained for the dSphs and in reasonable agreement with the empirical function of McGaugh et al. (2016), which reproduces MOND phenomenology.