Similarly, synaptoneurosomes derived from early AD cases and individuals with mild cognitive impairment show increased expression of neuroplasticity and synaptic transmission genes such as synaptic vesicle glycoprotein 2A (SV2A), growth associated protein 43 (GAP43), lipid phosphate phosphatase-related protein type 4 (LPPR4), glutamate receptor ionotropic AMPA 2 (GRIA2), cholinergic receptor muscarinic 3 (CHRM3), and 5-hydroxytryptamine receptor 2A (HTR2A) (Williams et al., 2009). Here, HTR2A is linked to Alzheimer disease.