GPD1 and hypertriglyceridemia: In particular, homozygous or compound heterozygous mutations in genes that alter lipoprotein lipase (LPL) activity, like LPL itself, APOC2, LMF1 (lipase maturation factor 1), GPIHBP1 (glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1), APOA5, and GPD1 (encoding glycerol-3-phosphate dehydrogenase 1) are associated with high TG, although both severe forms of hypertriglyceridemia and moderate-to-mild hyperglycemia are usually of polygenic origin (10, 11).