Triglycerides are one of the main sources of energy for humans, since they are storage molecules composed of fatty acids that can undergo beta-oxidation of fatty acids when they need energy (DR de Assis et al, 2003). Medium-chain acyl-CoA dehydrogenase deficiency (MCAD deficiency) is the most commonly diagnosed mitochondrial fatty acid β-oxidation disorder that prevents the conversion of fatty acids to energy (Rinaldo et al., 2002). MCAD deficiency is caused by mutations in the gene coding for the MCAD enzyme and the disorder occurs in 1 in 17,000 people, with the highest frequency in Northern European populations (Kompare & Rizzo, 2008; Rinaldo et al., 2002). Individuals are often diagnosed using genetic and molecular testing by looking at DNA and the contents of urine samples (Matern & Rinaldo, 2012). Newborn screening can help identify affected individuals before symptoms appear and take preventative measures against this disorder (Kompare & Rizzo, 2008). MCAD normally metabolizes medium-chain acyl-CoAs in the matrix of mitochondria. In fatty acid β-oxidation, MCAD catalyzes the dehydrogenation of acyl-CoAs with a chain length of four to 12 carbon atoms (Matern & Rinaldo, 2012). In MCAD deficiency, this initial dehydrogenation phase of the beta-oxidation process is significantly hindered, resulting in ineffective degradation of fatty acids. A deficiency of the MCAD enzyme is caused by premature degradation due to an accumulation of proteins and assembly of improperly folded tetramers. Beta-oxidation is severely affected because the enzyme also has reduced enzymatic function due to higher Km values ​​for medium-chain fatty acid substrates and lower affinity for its substrates (Kieweg et al., 1997). Because energy access via beta-oxidation. ..... half of the paper ...... which is catalyzed by b-ketoacyl CoA thiolase. The products are acetyl-CoA and a long-chain fatty acyl CoA that is 2 carbons shorter than the original fatty acyl CoA. A complete cycle of β-oxidation cleaves 2 carbon atoms from the fatty acid chain, and the process continues until the entire fatty acid chain is broken down into acetyl propinoyl CoA. For example, an 18-carbon chain fatty acid would have to go through 9 cycles of β-oxidation to be completely metabolized. Therefore, a normal ACADM gene will code for a fully functional medium-chain specific acyl-coenzyme A dehydrogenase. In fatty acid β-oxidation, the MCAD enzyme is responsible for catalyzing the initial step of the mitochondrial β-oxidation pathway for medium-chain fatty acids (C6-C12). The initial step is crucial to allow progression of the β-oxidation pathway. MCAD and β-oxidation deficiency