PPARGC1A and amyotrophic lateral sclerosis: The framework also incorporates opposing phosphoinositide 3-kinase (PI3K)/AKT/mechanistic target of rapamycin (mTOR) and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α) pathway patterns that may distinguish ALS from frontotemporal dementia (FTD) within an aging context.