Table 1 Eligible IMD (12 of these 31 diseases were represented in this interview study, shown in italics, with multiple interviews for some diseases)

Amino acid disorders:

  Phenylalanine hydroxylase deficiency

 Homocystinuria

  Maple syrup urine disease

  Tyrosinemia Type I

Urea cycle disorders:

 Arginase deficiency

 Argininosuccinic acidemia

 Carbamyl phosphate synthetase deficiency

  Citrin deficiency

 Citrullinemia

 Hyperornithinemia-Hyperammonemia-Homocitrullinuria syndrome

 N-acetylglutamate synthetase deficiency

  Ornithine transcarbamylase deficiency

Fatty acid oxidation disorders:

  Medium chain acyl-CoA dehydrogenase deficiency

 Very long-chain acyl-CoA dehydrogenase deficiency

  Carnitine uptake defect

  Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency

 Trifunctional protein deficiency

Organic acid disorders or ‘other’ IMD:

 ß-Ketothiolase deficiency

  Glutaric acidemia type I

 HMG-CoA lyase Deficiency

 Isovaleric acidemia

 3-Methylcrotonyl-CoA carboxylase deficiency

 Methylmalonic acidemias

 Propionic acidemia

 Guanidinoacetate methyltransferase deficiency

  Mucopolysaccharidosis type I

 Farber disease

  Galactosemia

  Glycogen storage disease type 1

 Multiple carboxylase/biotinidase deficiency

 Pyridoxine-dependent epilepsy