Recently, a report states that transient over-expression of Dnmt3a2, a Dnmt3a isoform, in mouse hippocampus can restore age-associated cognitive deficits and inhibition of hippocampal Dnmt3a2 expression by shRNAi leads to a damage in young mouse cognitive behavioral [62-63]. The gene discussed is DNMT3A; the disease is Cognitive impairment.