Two forms of CX3CL1 display differential activity in adeno-associated virus-treated CX3CL1 knockout mice; specifically, knocking out CX3CL1 leads to severe cognitive deficits, which can be mitigated by sCX3CL1 treatment, while mCX3CL1 can only partially alleviate them [23]. The gene discussed is CX3CL1; the disease is Cognitive impairment.