Journal Mobile

D Fitzpatrick
Journal Issue: 
Volume 36: Issue 2: 2006




Inborn errors of metabolism are genetically determined interruptions of one (or several related) metabolic pathway(s). Clinical symptoms are caused by deficiency of the pathway product and/or toxicity resulting from the accumulation of an intermediary compound.  Inborn errors of metabolism are mostly recessive disorders, with  clinical  symptoms  rare  in  heterozygous  individuals.  The  genetic defects  involve  homozygous  (autosomal)  or  hemizygous  (X-linked)  mutations  in genes encoding proteins with a single enzymatic function.  However, interruptions in biochemical pathways may also result from mutations affecting the bioavailability of  an  enzymatic  co-factor  or  disordered  transport  of  the  enzyme  across intracellular membranes. In the latter two circumstances it is likely that more than one enzymatic process will be affected.

The  five  main  modes  of  presentation  of  IEM  in  the  neonatal  period  are  acute intoxication, energy  deficiency, organomegaly, profound  central  hypotonia, and malformations. The common diagnoses in each of these groups will be presented, with brief descriptions of the currently available options for diagnosis and therapy.