Briefly, NfL is correlated with the HTT levels,17, 27, 28, 29, 30, 31, 32, 33, 34 baseline motor and cognitive deficits, magnetic resonance imaging (MRI) caudate and putamen volumes,35 HD‐ISS stage,25 and Prognostic Index.36, 37. This evidence concerns the gene NEFL and Cognitive impairment.