UCHL1 and Alzheimer disease: The distributions of the UCHL1 genotypes were in Hardy-Weinberg equilibrium for the control group (P = 0.602 for AA, P = 0.692 for AC and P = 0.846 for CC) as well as for the AD group (P = 0.436 for AA, P = 0.647 for AC and P = 0.825 for CC).