Decreased CSF levels of homovanillic acid in ALS patients.

Levels of homovanillic acid (MVA) were measured in lumbar cerebrospinal fluid from 24 patients affected by amyotrophic lateral sclerosis (ALS) and compared with those found in 11 patients with Parkinson's disease (PD) and 10 patients with lumbar disc herniations who served as controls. Mean HVA levels were significantly decreased in ALS and PD patients. These findings are consistent with impairment of central dopaminergic systems in ALS as well as suggesting degeneration of neuroanatomical structures other than motor neurons.