Nomenclature

Inborn errors of metabolism (IEMs) represent a large class of rare genetic disorders. The first IEM was described in 1902 by Sir Archibald Garrod. Since then, many more have been described, variously estimated as >600 or >700. We established a proposed nosology of IEMs, by first defining specific criteria to include a disorder as an IEM, in an attempt to create a self-consistent schema. Our initial approach identified 1015 well-characterized inborn errors of metabolism described in the literature. In addition, there were 111 less well-characterized conditions that may be IEMs but do not meet strict criteria for inclusion in the current nosology, although it is likely that many of these provisional IEMs will eventually be confirmed.

By necessity, the nosology is subject to constant revision as a result of the rapid pace of progress in the field of genetics. Thus, as new disorders are discovered, and our understanding of the pathophysiology of existing disorders continues to improve, frequent updates to the current nosology will be critical to maintain its usefulness. The purpose of this website is to facilitate the continuous digital update of the nosology via the IEMbase.