ABSTRACT
This chapter explores the way in which the new genetics impacts on disease classification. Genetics can lead to more refined classification and subdivision but it can also lead to confusion and ambiguity. The chapter examines the way in which disease classifications actually change as a result of genetic information. It presents two example diseases which have undergone reclassification as a result of genetic information: cystic fibrosis (CF) and diabetes. Prior to the discovery of the gene that codes for CF Conductance Regulator, the classification of CF was based on clinical symptoms, with help from some laboratory-based tests. While the CF classification has expanded due to genetic explanation, diabetes has undergone 'splitting' into numerous sub-divisions. In CF, the sweat test helped incorporate pancreatic insufficiency into the spectrum of conditions classed as CF, and in diabetes, autoimmune explanations beyond the simple human leukocyte antigens system contributed to the subdivision of the classification system.
