Amino acidopathy

Amino Acids, Thin-layer chromatography has found wide application in the clinical chemistry laboratory. An application that is practicable in the Laboratory of Neonatology is the screening of serum and urine for the amino acidopathies. In order to do this we use a micro ultrafiltering apparatus which has been designed in our laboratory (37). This is seen in Figure 29. 

Several classes of inborn errors of metabolism in addition to inborn errors of urea synthesis can cause neonatal hyperammonemia. These include organic acidurias, fatty acid oxidation defects, amino acidopathies, and mitochondrial respiratory chain disorders. All of these disorders have a number of features in common. Labor and delivery tend to be normal, and there are no predisposing risk factors. Clinical features present after 24 h of life and are progressive. They are inherited, and thus a family history of previously affected children or neonatal deaths may be present. While most are inherited in an autosomally recessive manner, ornithine tran-scarbamoylase (OTC) deficiency is X linked, and a family history of affected males in the maternal pedigree is not uncommon. 

Rapid Screening Methods for the Detection of Inherited and Acquired Amino-acidopathies Abraham Saifer... 

Given the risk of metabolic decompensation during pregnancy and postpartum period, women with amino acidopathies or urea cycle defects should be followed by an obstetric clinic specializing in high-risk pregnancies [1]. Frequent assessment of fetal growth is also needed. For successful maternal and fetal outcomes, a multidisciplinary approach is required with input from both the obstetric and metabolic teams [4,18, 21]. 

Delivery and the postpartum period are catabolic processes, and women with amino acidopathies or UCD are at high risk for metabolic decompensation during these times. The risk may be greatest for women with classical forms of these disorders, although severe decompensation has been reported in women considered to have milder phenotypes [14, 19]. The risk for decompensation increases if delivery is prolonged and/... 

Chalmers RA, Purkiss P, Watts RWE (1980) Screening for organic acidurias and amino acidopathies in newborns and children. J Inher Metab Dis 3 27-43... 

Amino acids Amino acidopathies (PKU, tyrosinemia type I) Dried blood plasma, urine ESI-MS/MS [12]... 

Table 9.1 Organic acidurias that present with an acute unexplained illness in the newborn and infant. Those associated with a characteristic and diagnostic amino acidopathy are indicated with an asterisk. 

Amino acid changes can be of a secondary nature and a clue to other types of metabolic disorders such as galactosemia, organic acidopathies and pyruvate metabolic disorders. 

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