Sites of genetic defects that impair lipid metabolism in muscle

ATGL: adipose triglyceride lipase; Carn: carnitine; CoA: coenzyme A; CPT1: carnitine palmitoyl transferase 1; CPT2: carnitine palmitoyl transferase 2; Cyt c: cytochrome c; enolyl CoA, 3-hydroxy FA-CoA, 3 keto FA-CoA are intermediates in beta oxidation ultimately yielding acetyl-acyl-coenzyme A (for oxidation by the tricarboxylic acid cycle and a fatty acyl-coenzyme A (FA-CoA) shortened by two carbons for further beta oxidation; ETF: electron transfer flavoprotein (receives electrons from the dehydrogenase reaction catalyzed by VLCAD, MCAD and SCAD); ETFDH: electron transfer flavoprotein dehydrogenase (receives electrons from ETF, transfers them to coenzyme Q10 for oxidation via respiratory chain complexes III and IV); FFA: free fatty acid; GCI-58: protein involved in activation of ATGL; LCHAD: long chain hydroxy-acyl-coenzyme A dehydrogenase, one of the three enzymatic reactions (indicated by stars) catalyzed by mitochondrial trifunctional protein; LPIN1: protein involved in triglyceride synthesis; MCAD and SCAD: medium and short chain acyl-coenzyme A dehydrogenase; NADH: nicotinamide adenine dinucleotide; NADH produced in the reaction catalyzed by LCHAD is oxidized via complex I of the respiratory chain; OCTN2: carnitine transporter; Translocase: the carnitine, fatty acyl-coenzyme A transferase; VLCAD: very long chain acyl-coenzyme A dehydrogenase.