Triglycerides are a primary source of energy for humans, which are storage molecules composed of fatty acids that can undergo beta-oxidation of fatty acids when in need of 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 encoding 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 examining DNA, as well as the contents of urine samples (Matern and Rinaldo, 2012). Newborn screening can help identify affected individuals before symptoms appear and take preventive measures against this disorder (Kompare & Rizzo, 2008). MCAD normally metabolizes medium-chain acyl-CoAs in the mitochondrial matrix. In the β-oxidation of fatty acids, MCAD catalyzes the dehydrogenation of acyl-CoAs having a chain length of four to 12 carbons (Matern and Rinaldo, 2012). In MCAD deficiency, this initial dehydrogenation step of the beta-oxidation process is significantly hampered, leading to inefficient fatty acid breakdown. MCAD enzyme deficiency is caused by premature degradation due to accumulation of misfolded proteins and tetramer assembly. 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). Due to access to energy via beta-oxidation. ..... middle of paper ...... which is catalyzed by b-ketoacyl CoA thiolase. The products are acetyl-CoA and a long-chain fatty acyl-CoA which is 2 carbons shorter than the original fatty acyl-CoA. A complete cycle of β-oxidation cuts 2 carbons from the fatty acid chain, and the process continues until the entire fatty acid chain is broken down into acetylpropinoyl CoA. For example, an 18-carbon chain fatty acid would need to undergo 9 cycles of β-oxidation to be completely metabolized. Thus, a normal ACADM gene will encode 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 (C6-C12) fatty acids. The initial step is crucial to allow progression of the β-oxidation pathway. MCAD and β-oxidation deficiency