Inborn errors of metabolism that belong to the same biochemical pathway often have similar clinical features, are detected by the same diagnostic procedures (basic and special diagnostic tests), and are treated according to similar principles of emergency intervention and long-term management. These clinical aspects are reflected in the SSIEM classification of inborn errors of metabolism, which groups the large number of individual conditions according to their respective biochemical pathways or disease groups as well as common pathophysiological mechanisms. The SSIEM classification can be used for learning and understanding inborn errors of metabolism, provides a framework for textbooks and is expected to form the basis of the classification of inherited metabolic disorders in the forthcoming 11th edition of the international classification of diseases (ICD11).


Zschocke, J. (2014). SSIEM Classification of Inborn Errors of Metabolism. In: Physician’s Guide to the Diagnosis, Treatment, and Follow-up of Inherited Metabolic Diseases. Eds.: N. Blau, M. Duran, K. M. Gibson and C. Dionisi-Vici. Berlin-Heidelberg, Springer: 817-830.

    • Phenylalanine and Tetrahydrobiopterin
    • Tyrosine
    • Sulphur Amino Acids
    • Hyperammonemias
    • Glycine, Serine and GABA
    • Proline
    • Amino Acid Transport
    • Leucine, Isoleucine, and Valine
    • Cerebral Organic Acidurias
    • Ethylmalonic Encephalopathy
    • Folate Metabolism and Transport
    • Vitamin B6
    • Molybdenum Cofactor
    • Vitamin B12
    • Biotin
    • Thiamine
    • Riboflavin and CoQ
    • Mitochondrial Fatty Acid Oxidation
    • Carbohydrates
    • Glucose Transport
    • Pyruvate Carboxylase and Pyruvate Dehydrogenase
    • Krebs Cycle
    • Hyperinsulinism
    • Mitochondrial Oxidative Phosphorylation
    • Ketone Bodies
    • Peroxisomals
    • Lysosomal Storage Disorders
    • Neuronal Ceroid Lipofuscinoses
    • Oligosaccharidoses
    • Sialic Acid
    • Mucopolysaccharidoses
    • Hyperoxalurias
    • Cystinosis
    • Congenital Disorders of Glycosylation
    • Neurotransmitters Metabolism and Transport
    • Creatine metabolism and Transport
    • Heme Synthesis and Porphyrias
    • Bile Acid Synthesis and Biliary Transport
    • Polyol Metabolism
    • Cholesterol Synthesis
    • Adrenals and Gonads
    • Leukotrienes
    • Copper, Zinc and Iron
    • Purine and Pyrimidine
    • Glutathione and γ-Glutamyl Cycle
    • Lipoproteins

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