HADHB function in beta-oxidation The genetics of<unk>  is based on mutations in the HADHA and HADHB genes which cause this disorder. These genes each provide instructions for making part of an enzyme complex called mitochondrial<unk><unk> . This enzyme complex functions in mitochondria, the energy-producing centers within cells: mitochondrial<unk><unk>  contains three enzymes that each perform a different function. This enzyme complex is required to metabolize a group of fats called long-chain fatty acids. These fatty acids are stored in the body's fat tissues and are a major source of energy for the heart and muscles. During periods of fasting, fatty acids are also an important energy source for the liver and other tissues. Mutations in the HADHA or HADHB genes that cause<unk>  disrupt all functions of this enzyme complex. Without enough of this enzyme complex, long-chain fatty acids cannot be metabolized. As a result, these fatty acids are not converted to energy, which can lead to some features of this disorder. Long-chain fatty acids may also build up and damage the liver, heart, and muscles. This abnormal buildup causes other symptoms of<unk> . The mechanism of this condition indicates that the mitochondrial trifunction<unk>  catalyzes 3 steps in mitochondrial beta-oxidation of fatty acids: long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD), long-chain enoyl-CoA hydratase, and long-chain thiolase activities.<unk><unk>  deficiency is characterized by decreased activity of all 3 enzymes. Clinically,<unk><unk>  deficiency usually results in sudden unexplained infant death, cardiomyopathy, or skeletal myopathy.
Mitochondrial trifunctional protein deficiency
Mitochondrial complex II deficiency
Medium-chain acyl-coenzyme A dehydrogenase deficiency
Carnitine-acylcarnitine translocase deficiency
Glutathione synthetase deficiency
Systemic primary carnitine deficiency
Creatine transporter defect
Carnitine palmitoyltransferase II deficiency