[Molecular biology diagnostics of hereditary metabolic diseases].

Metabolic diseases are often a result of monogenic inheritance and are suitable subjects for molecular diagnosis. Much progress has been made on research into this group of diseases, and further advances are expected after the completion of the Human Genome Project (HUGO) and as a consequence of improved molecular genetic methods. Although it is possible to diagnose many metabolic disorders by biochemical analyses of enzyme function, the underlying molecular genetic defects must be identified in order to be able to make accurate diagnoses of patients and their relatives. A molecular diagnosis is also a pre-condition for gene therapy. It is of paramount importance that more knowledge is gained of the correlation between genotype and phenotype for the genetic counselling of patients and their families. Important challenges at the present time are how to achieve a better understanding of the molecular and metabolic basis for the way in which diseases manifest themselves clinically and the factors which modify the phenotype.