Genetic and molecular basis of human hereditary diseases.

A.N AREA of significant medical progress over the past decade has been the recognition and the biochemical characterization of an ever-increasing number of human hereditary diseases (1). Some of the practical consequences have been the development of objective chemical and biochemical methods for more precise diagnoses of a large number of these diseases (many of them newly recognized) and the opening of new approaches for treatment of clinical disorders including some types of mental retardation that have, in time past, been regarded as hopeless medical curiosities. The prospect of more widespread use in clinical laboratories of automated analytic systems for chemical determinations gives promise of the detection of aim even larger number of genetically determined abnormalities of body chenmistry in the years ahead. Although many of these inherited diseases are relatively rare disorders, there are considerations that cause these disorders to assume a far greater importance to the medical and scientific community than is revealed by their statistical incidence.