[The contribution of molecular genetics to hereditary neurometabolic disorders].

In this article we review the main contribution of molecular genetics to understanding hereditary neurometabolic disorders. This includes improvement in diagnosis, especially in X chromosome linked disorders and illness due to the protein or gene expression in tissues which are difficult to obtain. Moreover molecular biology, as a diagnostic tool, has contributed decisively to genetic counselling by permitting firm diagnosis of carriers and prenatal diagnosis. Other important contributions, although more minor, are determination of the prognosis and establishment of individualized treatment based on the genotype. We also review the relation between the disease and the susceptibility allele, the possibility of making genetic population studies and of establishing presymptomatic diagnoses. It is concluded that understanding the molecular basis of a particular disorder has opened the way to diagnosis and prognosis. It also opens the door to genetic therapy, the study of other factors which may affect the action of genes and especially the proteinome.