Psoriasis is defined as an inherited skin disease. While we haven't isolated the gene yet, we have discovered that there is more than one gene coding it -- it has a different mutation in different families.
Like many diseases, once you start looking at the molecular biology, while the clinical picture of psoriasis can be fairly uniform, the genetic picture of psoriasis never is. Since the clinical picture of psoriasis is not by any means uniform, so this is really comes to no surprise.
The ultimate treatment of psoriasis will depend on the molecular biology.
