INSIG1 and Alzheimer disease: While the expression at mRNA or protein levels of STARD4, INSIG-1 and mature SREBP2 (mSREBP2) seems to be similar between AD, DS and control samples (Figure 1), cortex from patients with DS exhibited a significant overexpression of transcripts for the mitochondrial carrier STARD1 (Figure 1A), which translated at the protein levels (Figure 1B).