Overall, NfL immunoreactivity was significantly increased in the PDD/DLB group compared to controls (+ 30%, P = 0.037), and tended to be increased in PDD/DLB compared to PD (P = 0.058), while it did not differ in PD compared to controls (P = 1.000) (Fig. 2b, and Additional file 2: Fig. S3b for representative images). This evidence concerns the gene NEFL and Parkinson disease.