Simplifying genetic disorders

Simple genetic diseases, such as cystic fibrosis and thalassaemia are just that — simple. A single gene underlies them. Finding it is like climbing a steep hill — hard work but straightforward. Complex disorders, such as asthma and type 2 diabetes, by contrast, have many components, which makes finding a cause more like scaling Everest — far harder, requiring more specialist equipment and the strong possibility of failure.

In work published in the October issue of Nature Genetics, University of Chicago researchers have cleared a path to studying the genetic foundation of type 2, or non-insulin-dependent diabetes mellitus (NIDDM). In a study of a Mexican-American population and two white populations (Finns and Germans) they have found that small genetic variations, called single-nucleotide polymorphisms (SNPs), in a particular gene tend to occur more often in diabetics than in healthy relatives. Although finding a common genetic variation in family groups affected...