Defective genes in Presenilin-1 (PS-1) has been related with high risk in develop a familial form of Alzheimer disease (AD). The mutation PS-1 E280A has been found in a large kindred of Antioquia, Colombia. We investigated the influence of AD-associated E280A genotype on brain activity in young asymptomatic subjects. We examined quantitative EEG in a cohort of 30 healthy non-demented individuals divided into 15 non-carriers (age 31.5 ± 5.8 years) and 15 E280A carriers (age 28.8 ± 5.1 years) during resting and a memory task. Power spectrum was calculated in delta (0. 5-4. 0 Hz), theta (4. 0-8. 0 Hz), alpha-1 (8. 0-10. 0 Hz), alpha-2 (10. 0-13. 0 Hz), beta (13. 0-25. 0 Hz) and gamma (25. 0-50 Hz) band frequencies for four regions of interest. Changes were evaluated in different conditions by ANOVA analysis and in the bands and regions where statistical differences were found we performed a discriminant analysis (DA) through leave-one-out crossvalidation. Theta frequencies band was significantly lower in carriers compared with controls (p =0.008) during encoding. In resting condition a significant decrease was found in theta (p =0.0001) and an increase in alpha-2 frequencies (p =0.037) in carriers compare with controls. DA separately for these measures showed a high group discrimination (66,7%) in temporal region for theta and alpha-2 in resting condition. A paired combination of the measures showed higher discrimination (76,7%) for the encoding condition between frontal y central regions in theta. Early changes in theta frequencies were observed in the EEG recordings for both resting and memory conditions. The combination of power spectrum in the theta band for central and frontal regions during encoding process showed a high discrimination between carriers and non-carriers. Our findings could be used as clinical markers in this population but additional analysis are necessary including subjects in different phases of the disease.