The association analysis of SNPs with cognitiveabilities such as memory, educational background, and verbalnumericalabilities, revealed the involvement of genes thatplay an important role in brain development and functioning.These genes include CADM2 (encodes a synaptic cell adhesionprotein in the central nervous system), CYP2D6 (encodes acytochrome metabolizing serotonin and neurosteroids) andAPBA1 (encodes a protein that interacts with the amyloid precursorin Alzheimer’s disease). Here, CYP2D6 is linked to early-onset autosomal dominant Alzheimer disease.