APOE and Alzheimer disease: There is a need to correctly identify the risk factors for epilepsy in this particular population: 1- there is a lack of information to know whether the risk of epilepsy both in childhood and in relation to the development of symptomatic AD varies depending on whether it is a subject with complete trisomy versus a mosaic or translocation; and 2- the role of the main genetic risk factor for sporadic AD which is the ApoE4 allele, linked to earlier onset AD and increased risk of epilepsy in sporadic AD, in the risk of developing LOMEDS is not known.