Developmental delay: when to suspect and how to investigate for an inborn error of metabolism.

The purpose of this review is to provide a practical guideline on the suspicion and investigation of inborn errors of metabolism (IEMs) as cause of developmental delay. Developmental delay is a common paediatric problem. Inborn errors of metabolism are a rare cause of developmental delay. However, it is important to detect IEMs for several reasons: accurate counselling may be given regarding recurrence risk; metabolic decompensation may be avoided; and specific treatments may be available. Certain clinical situations are more likely to point to an IEM as the cause of developmental delay. This review highlights the risk factors in the history, the important examination findings, and the appropriate biochemical investigation of the child with developmental delay. Following these guidelines makes "missing" an IEM unlikely.