Molecular genetics as a diagnostic service

Abstract

The major advances in mapping and cloning disease genes during the past few years have been applied with minimal delay to such practical areas as prenatal diagnosis and carrier detection. Following early applications for the thalassemias, important disorders such as the muscular dystrophies, haemophilias, cystic fibrosis, and Huntington's disease have all come within the orbit of molecular genetics, and most of the other major Mendelian conditions are likely to follow in the near future. So far these developments have been reported and analysed in terms of the individual disease or group of diseases, and there is no doubt as to their effectiveness in the context of such disorders as β thalassemia or Duchenne muscular dystrophy. Much less attention has so far been given to the overall development of diagnostic molecular genetics and to the optimal organisation of services based not on a single disease, but on a broad range of genetic disorders. As the number of diseases where such applications are feasible increases, this overall approach becomes a matter of urgency. Such assessments as have been done so far have been based largely on indirect evidence, especially in relation to the economic aspects. The reports in this tissue of the Journal are thus especially timely, as they are based on the hard experience of units initiating and developing a molecular genetics service. Four years ago the Health Departments in England and Wales funded three centres for a trial three year period to provide the foundations of a molecular diagnostic service; simultaneously, an independent evaluation of their results and progress was commissioned to allow an objective assessment of the value of this work. Results are presented here from one of the centres involved (Manchester), which clearly show the extent and pace with which this field has grown and matured. One of the other centres (Cardiff) has already presented comparable data from its own experience, so that a picture is now emerging as to how these techniques are being related to new discoveries, to clinical demands, and to existing genetic and other services.