PFN1 and amyotrophic lateral sclerosis: On the other hand, iPSC-derived microglia-like cells with ALS-linked PFN1 mutations exhibit lipid dysmetabolism, autophagy dysregulation, and impaired phagocytosis, implicating a toxic gain of function for mutant PFN1 in autophagic and endo-lysosomal pathways, with rapamycin shown to rescue phagocytic dysfunction [93].