Post-mortem studies have also reported reduced binding of the radioligand [3H]4-DAMP, under CHRM1/CHRM3/CHRM4/CHRM5 selective assay conditions, in the orbitofrontal cortex from subjects with Alzheimer's disease who had significant psychotic symptoms (Tsang et al., 2008). This evidence concerns the gene CHRM4 and early-onset autosomal dominant Alzheimer disease.