Specifically, ibrutinib, a Bruton’s tyrosine kinase (BTK) inhibitor approved by the FDA for chronic lymphocytic leukemia, exhibits therapeutic efficacy against deficits in cognitive/synaptic function and AD pathology in AD mice when injected intraperitoneally at a lower dosage (10 mg/kg, i.p., daily for 2 weeks) or by oral gavage at a higher dosage (30 mg/kg, p.o., daily for 1 month) [6]. This evidence concerns the gene BTK and Alzheimer disease.