NEFL and amyotrophic lateral sclerosis: However, some studies reported higher blood NFL concentrations in female ALS patients: in one cohort, the finding could be explained by females suffering from more advanced disease (and being on average older than male patients), but in general, it warrants further investigation (Lu et al., 2015; Benatar et al., 2020; De Schaepdryver et al., 2020).