However, it might be possible that these changes represent only full-blown AD clinical pathology since the analysis of samples from young healthy individuals at risk of developing AD, due to the carriage of at least one ApoE4 allele, has demonstrated reduced GSSG levels in whole blood and increased amount of GPx and glutamylcysteine ligase (GCL) in lymphocytes when compared to the ApoE3/ApoE3 controls. Here, APOE is linked to Alzheimer disease.