FASN and neutropenia: It has been previously reported that bone marrow-specific deletion of either fatty acid synthase (FAS), which catalyzes the first committed step in de novo lipogenesis, or of peroxisomal reductase activating PPARγ (PexRAP), which acts in ether lipid synthesis following generation of the ether bond by AGPS at the peroxisome, result in neutropenia, but not monocytopenia, due to cell-autonomous loss of neutrophils via endoplasmic reticulum stress and apoptosis [25].