The value of the study of natural history in genetic disorders and congenital anomaly syndromes.

The study of the natural history of genetic disorders and syndromes with congenital anomalies and dysmorphic features is a challenging and often neglected area. There are many reasons to pursue this type of research but it requires special clinical skills and a considerable amount of hard work. Setting up protocols and collecting data is complex and time consuming. Frequently, helpful clues for a particular disorder come from the study of the natural history of other disorders. Older affected subjects and unique cases with unusual features are often most important in unravelling the 'normal' course of a disease or recognising the basic defect. The study of natural history from individual patients and their records is complementary to population or registry based studies because it identifies individual variations and clinical heterogeneity. The understanding of the natural history of a particular disorder is of importance both to the affected person and their family and to the physicians caring for them. It is also useful to the basic researcher trying to determine the pathogenetic mechanism causing the disorder. In many ways, clinical geneticists have learned the art of caring for patients, as well as the challenges of clinical genetics, by becoming apprentices to and studying in depth specific disease entities.