As discussed above, higher levels of the Col6a1 transcript and protein were observed in hippocampal neurons of mice expressing mutant human APP, and a higher expression of COL6A1, COL6A2 and COL6A3 mRNA was also detected in the dentate gyrus (Box 1) of Alzheimer's disease patients compared with cognitively normal controls (Cheng et al., 2009). Here, COL6A1 is linked to Alzheimer disease.