Perimortem laboratory investigation of genetic metabolic disorders

Over 400 rare, biochemically diverse genetic metabolic disorders (inborn errors of metabolism) have been described and the list is growing by the month. Although recent advances in the diagnosis and treatment of these disorders have substantially improved the prognosis for many of them, including those presenting in the neonatal period, a proportion of affected individuals die before the diagnosis can be confirmed and, in some cases, before the diagnosis is even considered. This review will provide an outline of the range of clinical presentations seen in neonates with genetic metabolic disorders and provide a practical approach for rapid biochemical screening for these disorders. In addition, suggested guidelines are given for the collection of relevant samples in the perimortem period, the aim being to maximize the chance of identifying any underlying genetic metabolic disorder.