[Biological diagnosis of hereditary metabolic diseases. From selective screening to the mutant-cell bank].

The experience of a specialized laboratory for the biological diagnosis of inborn errors of metabolism in selected pediatrics patients is reported. The strategy starts with a wide testing of blood and urine, as many inborn errors of metabolism can be detected through testing of blood and urine for increased concentration of specific metabolites known to be associated with the genetic defect. Then enzymatic or DNA studies are performed to confirm the diagnosis. The mutant cells mostly fibroblasts are stored in a cell bank and available for other research.