When the frequency distributions of PSD-95 puncta diameter were analyzed there was an apparent increase in small puncta frequency (<0.35 μm: Figures 4B,C) but crucially, a reduction in PSD-95 puncta density was observed in patients with advanced symptomatic AD that suggested they had a lower synaptic density (Figure 4D). The gene discussed is DLG4; the disease is Alzheimer disease.