The importance of the EC in the AD pathological cascade has recently been underscored by the publication of a case report51 describing a member of the world's largest known kindred with autosomal dominant AD due to the PSEN1‐E280A mutation, who was additionally heterozygous for a rare mutation in the RELN gene encoding reelin and whose age of dementia onset was delayed by almost three decades compared to other kindred members. This evidence concerns the gene RELN and Alzheimer disease.