Different diseases may share genetic links

Philippa Brice

2 May 2012

Genetic research is shedding light on how apparently very different diseases may be more closely related than previously supposed.

Determining the genetic causes and contributions to different diseases is important for understanding how diseases arise, and how it may be possible to prevent or treat them. Since the completion of the first human genome sequence, and with rapid advances in sequencing technology, there is a veritable explosion in genetic data about all kinds of diseases and conditions.

One unexpected development in recent years is the emergence of hitherto unsuspected genetic connections between different diseases. It has been known for some years that mutations in certain key genes such as p53 and KRAS are a common feature of different cancers. Most recently, research has suggested that breast cancer may effectively be ten separate diseases based on the underlying genetic mutations (see previous news), which could mean that an entirely new approach to diagnosis and treatment is indicated. Similarly, research into chronic fatigue syndrome has suggested that genetic differences may define seven different subtypes of disease (see previous news).

However, genetic links are also being found between very different diseases; for example, type 2 diabetes and Crohn's disease; type 1 diabetes, lupus and rheumatoid arthritis. By using a systems biology approach, which considers the complex interactions between DNA, RNA and proteins in living systems, researchers are trying to make sense of genetic and related links between diseases.

Comment: Although the complexity of interactions examined in systems biology is daunting – requiring new developments in computing to handle the volumes of data – this is an important area of research. As our conceptual understanding of a disease previously considered as a single entity, such a breast cancer, evolves, we can see how our whole approach to medicine may be in some senses flawed. Diseases that seem logically to share a common basis may not do so; apparently disparate diseases may eventually prove to be related.

These preliminary results suggest that our current concept of genomic medicine – exciting as it is - may actually evolve much further in the coming years. Although this is likely to remain largely a research question for the foreseeable future, oncologists and certain other specialties such as rheumatology are already taking on board new approaches based on genomic insights; other specialties may follow.