GDNF and supranuclear palsy, progressive, 1: In the context of correlations which were observed between the atrophic changes e.g. in the mesencephalon in the MRI and the growth of GDNF, especially in the evaluations of PSP-RS and PSP (without indication of subtypes), it may be assumed that the growth of GDNF particularly in the CSF is an indicator of tendency towards PSP-RS subtype.