With respect to disease subgroups, there was a trend toward higher mean serum NF-L levels in PSP-cortical (58.6 pg/L) vs PSP-RS (45.3 pg/L) and PSP-subcortical (41.6 pg/L) and in CBS-4RT (52.4 pg/L) vs CBS-AD (36.5 pg/L) (Figure 3). The gene discussed is NEFL; the disease is Alzheimer disease.