Table 2

Table demonstrating IEM tested for by first-line metabolic investigations25

(number of conditions identified)
Conditions identified
Plasma amino acids, n=13l.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=7Cobalamin C, D, E, F and G deficiencies
Homocystinuria, MTHFR deficiency
Acylcarnitine, n=7Ethylmalonic encephalopathy
Isovaleric acidemia, tyrosinemia type II
Cobalamin C, D and F deficiencies, 3-methylcrotonyl glycinuria
Urine organic acid, n=22β-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=4Hunter syndrome (MPS II)
Hurler syndrome (MPS I)
Sanfilippo syndrome A, B, C
Sly syndrome (MPS VII)
Purines and pyramidines, n=3Molybdenum cofactor deficiency type A
Pyrimidine 5-nucleotidase superactivity
Lesch-Nyhan syndrome
Oligosaccharides, n=2α-Mannosidosis
Urine creatine metabolites, n=3AGAT 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.