In another analysis, the mean MAO-B activity (nmol/h per 107 platelets ± S.D.)in the different groups was as follows: control group (age range: 46-85 years) = 2.01 ± 0.73; untreated PD group (age range: 26-76 years) = 1.80 ± 0.54; levodopa-treated PD group (age range: 60-77 years) = 1.56 ± 0.55; and AD group (age range: 57-88 years) = 1.78 ± 0.87 [80]. This evidence concerns the gene MAOB and Alzheimer disease.