Without the enzymatic activity of<unk> -CoA<unk> , cellular Mal-CoA increases so dramatically that at the end it is instead broken down by an unspecific short-chain acyl-CoA hydrolase, which produces malonic acid and CoA. Malonic acid is a Krebs cycle inhibitor, preventing the cells to make ATP through oxidation. In this condition, the cells, to make ATP, are forced to increase glycolysis, which produces lactic acid as a by-product. The increase of lactic and malonic acid drastically lowers blood pH, and causes both lactic and malonic aciduria (acidic urine). This condition is very rare, as fewer than 20 cases have been reported. By 1999, only seven cases of<unk>  had been reported in human in Australia; however, this deficiency predominately occurs during childhood. Patients from the seven reported cases of<unk>  have an age range between 4 days to 13 years, and they all have the common symptom of delayed neurological development. Similar study was conducted in Netherland, and found seventeen reported cases of<unk>  in children age range from 8 days to 12 years. Although we have not yet gained a clear understanding of the pathogenic mechanism of this deficiency, some researchers have suggested a brain-specific interaction between<unk> -CoA and CTP1 enzyme which may leads to unexplained symptoms of the MCD deficiency. Research has found that large amount of MCD are detached in the hypothalamus and cortex of the brain where high levels of lipogenic enzymes are found, indicating that MCD plays a role in lipid synthesis in the brain. Disturbed interaction between<unk> -CoA and CPT1 may also contributed to abnormal brain development.<unk> -CoA<unk>  plays an important role in the β-oxidation processes in both mitochondria and peroxisome. Some other authors have also hypothesized that it is the MCD deficiency induced inhibition of peroxisomal β-oxidation that contributes to the development delay.
Malonyl-CoA decarboxylase deficiency
Pyruvate kinase deficiency
3-Hydroxyisobutyryl-CoA deacylase deficiency
3-Methylcrotonyl-CoA carboxylase deficiency
Holocarboxylase synthetase deficiency
Glutaminase deficiency
2,4 Dienoyl-CoA reductase deficiency
Carbamoyl phosphate synthetase I deficiency