THOP1 and early-onset autosomal dominant Alzheimer disease: Out of the fifteen pathways identified, a third appear to be conserved: (1) liver X receptor/retinoid X receptor (LXR/RXR activation), (2) neuroprotective role of THOP1 gene in Alzheimer’s disease, (3) glutamate receptor signaling, (4) nNOS signaling in skeletal muscle cells, and (5) calcium signaling pathways.