FLT3LG and multiple system atrophy: In the discovery group, CSF FLT3L levels were significantly lower in PD (38.4 ± 11.9 ng/L; p < 0.01) and MSA (39.3 ± 12.4 ng/L; p < 0.05) compared with controls (47.8 ± 14.3 ng/L) but similar in MSA and PD (Figure 2A).