<unk>  are a class of<unk>  error of<unk>  disorders specifically affecting<unk><unk>  and<unk><unk> . An example is Lesch–Nyhan syndrome.<unk>  tests may be of use in identifying some of these disorders.
Inborn errors of purine–pyrimidine metabolism
Congenital disorders of amino acid metabolism
Adenine phosphoribosyltransferase deficiency
Hereditary folate malabsorption
Inborn errors of metabolism
Aromatic L-amino acid decarboxylase deficiency
Methylenetetrahydrofolate reductase deficiency
Ribosomopathy