Phenotypes in Behçet's syndrome.

Behçet syndrome (BS) is a multi-systemic complex disorder with unknown etiology and a unique geographic distribution. It could not be possible to include it into specific classification schemes and it is certainly not a uniform disease. Several cluster and association studies revealed that it has been composed of multiple phenotypes ascribing the principal problem such as skin-mucosa, joint, eye, vascular, neurological and gastrointestinal involvement. Each phenotype has its own characteristic demographic and clinical features as such their management strategies and prognosis differ substantially. Actually, the concept of phenotyping has been well known for some time and is considered one of the basic elements of the still continuing debate whether to call this entity 'disease' or 'syndrome'. Further supporting evidence comes from the observation of the geographical differences of disease expression. In this setting, BS resembles rather a construction made of several dynamic and interactive LEGO pieces of different shapes and colors. These pieces presenting phenotypes with their own disease mechanism have presumably different genetic determinants. The analysis of phenotyping could help us to identify this disorder and hence could contribute to find better ways of treatment.