Table 2.

Classes of inborn errors of metabolism (IEM) identified from studies

IEM class	Examples
Amino acid disorders	Phenylketonuria, homocystinuria
Organic acid disorders	Propionic aciduria, methyl malonic aciduria, isovaleric aciduria, biotinidase deficiency
Fatty acid disorders	Short or medium chain acyl-coenzyme A dehydrogenase deficiency (SCAD, MCAD)
Lysosomal storage disorders	Sphyngolipidoses (Fabry, Farber, Gauher and Niemann-Pick diseases), mucolipidoses, oligosaccharidoses (fucosidosis, mannosidosis)
Carbohydrate metabolism disorders	Galactosemia, Pompe’s disease (glycogen);
Urea cycle disorders	Citrullinemia, argininemia
Mitochondrial disorders	Leigh syndrome
Peroxisomal disorders	Zellweger syndrome, Refsum syndrome
Others*	Purine and pyrimidine disorders, metal disorders, porphyria and haematological disorders, lipid disorders and myelin metabolism disorders

*Returned too few data points to be included in the meta-analysis.