Progress in screening for inborn errors of metabolism.

The inborn errors of matabolism are a series of individually rare biochemical 
anomalies some of which cause serious clinical manifestations. They are of 
great interest to biochemists and geneticists, as well as to paediatricians 
and internist for whom they often present special diagnostic and therapeutic 
problems. The study of the inborn errors of metabolism also has 
implications in the fields of epidemiology and social medicine. The number 
of known inborn errors of metabolism has increased rapidly in recent 
years, and others, as yet unidentified, presumably await recognition. Only a 
few of these conditions can be treated now, but the realisation 
that early diagnosis is essential in order to achieve good results 
has stimulated interest in the possibility of examining either whole populations 
or selected predisposed groups of individuals for biochemical differences which characterise 
particular inherited metabolic diseases. This article reviews some recent developments with 
particular reference to the indications for such screening programmes and progress 
in the identification of previously unknown inborn errors of metabolism in 
otherwise homogeneous population groups. The inborn errors of metabolism are due 
to single gene mutations. Recognition of the asymptomatic individuals who are 
heterozygous for the abnormal gene causing the disease may be important 
clinically and the identification has to be considered as one aspect 
of metabolic screening for the inborn errors of metabolism. 