This means medical treatments can increasingly focus on differences between patients and become more personalised.

It has also become clear that no two illnesses are the same and that existing useful forms of treatment are not effective in all patients due to genetic, environmental, lifestyle and nutritional factors.

Extensive research has confirmed that there is a complex interplay of genetic and other factors in the vast majority of diseases. Besides endogenous and exogenous genetic factors, other factors like diet, environment and behaviour can influence the body's reactions independently of the actual causes of diseases.

As for genes, they can protect against or predispose humans to the development of many complex diseases such as cancer, heart ailments and diabetes, resulting in an overall risk for those who possess the predisposing genes.

These genetic risk factors can be either categorical or quantitative. For example, a gene variant acts categorically if a certain disease can occur only in its presence; gene variants acting quantitatively may have accumulative effects up to the critical point at which disease occurs.

With the deeper understanding of the human genome, medicine can become more personalised in the sense that there will be a broader range of therapeutic options for doctors to choose so that each patient is given the most suitable choice based on his or her genetic factors.

Currently there remains great fluctuation in the effectiveness of many drugs such as those for heart ailments, obsessive-compulsive disorders, asthma or cholesterol reduction, with efficacy ranging from 10-25 per cent to 40-70 per cent.

To improve the effectiveness of new drugs, the target groups for each new development will become smaller, and the use of these drugs will not be determined only by the molecular causes of diseases being treated but also by the pharmacogenetic profile of each patient.

As for the overall healthcare system, the outlook is one of further integration as one innovation gives rise to another. Personalised treatment means the need for individual diagnoses, while molecular diagnosis will lead to differentiated therapy. Both aspects will reach new heights in pace with the rapidly expanding technological possibilities.

In other words, drug research and development, diagnosis and therapy, information and prevention are evolving hand in hand towards more integrated healthcare. For instance, the concept of diagnosis will likely be extended beyond symptoms and clinical findings to include the molecular underpinnings of diseases and their treatment.

For disease prevention, which remains largely undeveloped and mostly based on maintaining a healthy lifestyle, tests such as for genetic predisposition and high cholesterol, for example, will likely expand rapidly in the near future so as to enable patients to receive more specific counselling.

Since an ailment is easier to treat if it is detected early, the era of molecular diagnosis will open up many new possibilities. This will be especially beneficial if individual-specific diagnosis is matched by a corresponding range of personalised treatments.

Overall, doctors' responsibilities will also increase significantly as they will have to deal with entirely new diagnostic resources, a considerably expanded range of therapies and, due to the unrelenting growth of the Internet, far better informed and more self-confident patients.

 Nophakhun Limsamarnphun

 nop1122@yahoo.com