Association of monoamine oxidase B alleles with age at onset in amyotrophic lateral sclerosis

An active role of monoamine oxidase B (MAO-B) in the pathogenesis of neurod egenerative disorders such as Parkinson's disease has been proposed as the enzyme is known to be a generator of free radicals which seem to be respons ible for neuron oxidative damage. We evaluated the influence of MAO-B in th e pathogenesis of the sporadic forms of Amyotrophic lateral sclerosis (ALS) by studying the MAO-B allele distribution in 51 patients and 71 healthy co ntrols. MAO-B did not directly result in a risk factor for ALS but seemed t o strongly influence age at onset. The mean ALS onset age was significantly higher in individuals carrying allele 5 compared to individuals without th is allele (60.4 +/- 8.1 vs. 52.1 +/- 10.3 years; P = 0.004). These results, in agreement with findings in the literature, suggest an increased MAO-B e xpression in ALS and support the hypothesis that neuronal cell death in neu rodegenerative diseases is triggered by astroglial reaction. (C) 1999 Elsev ier Science B.V. All rights reserved.