Table demonstrating IEM tested for by first-line metabolic investigations25
| Test (number of conditions identified) | Conditions identified |
| Plasma amino acids, n=13 | l.o. argininemia, l.o. argininosuccinic aciduria l.o. citrullinemia , l.o. citrullinemia type II CPS deficiency, HHH syndrome Maple syrup urine disease (variant) l.o. NAGS deficiency, OTC deficiency Phenylketonuria, tyrosinemia type II MTHFR deficiency, PDH complex deficiency |
| Plasma total homocysteine, n=7 | Cobalamin C, D, E, F and G deficiencies Homocystinuria, MTHFR deficiency |
| Acylcarnitine, n=7 | Ethylmalonic encephalopathy Isovaleric acidemia, tyrosinemia type II Cobalamin C, D and F deficiencies, 3-methylcrotonyl glycinuria |
| Urine organic acid, n=22 | β-Ketothiolase deficiency, MHBD deficiency Cobalamin A, B, C, D and F deficiencies Glutaric acidemia I, glutaric acidemia II HMG-CoA lyase deficiency, tyrosinemia type II Holocarboxylase synthetase deficiency 3-Methylglutaconic aciduria, 3-methylylcrotonyl glyciuria Methylmalonic acidemia, isovaleric acidemia Homocystinuria, propionic acidemia mHMG-CoA synthase deficiency SCOT deficiency, SSADH deficiency |
| Glycosaminoglycans, n=4 | Hunter syndrome (MPS II) Hurler syndrome (MPS I) Sanfilippo syndrome A, B, C Sly syndrome (MPS VII) |
| Purines and pyramidines, n=3 | Molybdenum cofactor deficiency type A Pyrimidine 5-nucleotidase superactivity Lesch-Nyhan syndrome |
| Oligosaccharides, n=2 | α-Mannosidosis Aspartylglucosaminuria |
| Urine creatine metabolites, n=3 | AGAT deficiency Creatine transporter defect GAMT deficiency |
Adapted from Van Karnebeek.25 Some conditions are identified by more than one test.
AGAT, arginine: glycine amidinotransferase; CPS, carbamoyl phosphate synthetase; GAMT, guanidino-acetate-N-methyltransferase; HHH, hyperornithinemia, hyperammonemia, homocitrullinemia; HMG-CoA, 3-hydroxy-3-methylglutaryl-CoA; l.o., late-onset form; MHBD, 2-methyl-3-hydroxybutyryl-CoA dehydrogenase; mHMG CoA, mitochondrial 3-hydroxy-3-methylglutaryl-CoA; MTHFR, methylenetetrahydrofolate reductase; NAGS, N-acetylglutamate synthetase; OTC, ornithine transcarbamylase; PDH, pyruvate dehydrogenase; SCOT, succinyl CoA 3-oxoacid CoA transferase; SSADH, succinic semialdehyde dehydrogenase.