NfL is a biomarker for adult-onset leukoencephalopathy with axonal spheroids and pigmented glia.

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a devastating disease characterized by rapidly progressing motor impairment and dementia with a mean age at onset of 43 years and a mean survival of 7 years.1 It is caused by autosomal dominant mutations in the CSF1R gene with almost complete penetrance, posing a 50% risk to each patientu0027s descendant to carry the mutation.1,2