During the last years an explosion of discoveries has taken place and it will continue for the coming years with undiminished pace. We are finding the genes for lupus and with this we will soon have the basis for the understanding of disease pathogenesis. Still, much of the previous knowledge is important, and still, great challenges lie ahead.
In this issue of Autoimmunity we have been able to assemble a sample of the most recent work on the genetics of lupus, but we have also wanted to provide an update on genes long before discovered as the complement genes and PTPN22. Lennart Truedsson and collaborators, and Lindsey Criswell and collaborators provide us with excellent and up-to-date reviews on these two topics. Two recent genes have been identified in lupus and understanding the mechanisms through which these confer susceptibility has become a major challenge in complex disease genetics not the least for lupus genetics. One of these genes is IRF5, and Kozyrev and collaborators provide us with an insight view of how functional polymorphisms in this gene may be conferring disease susceptibility. The identification of disease haplotypes has proven to be of major importance to understand disease risk.
Other aspects that cannot be left on the side are the genetics of clinical manifestations of lupus. Here, Namju and collaborators provide us with a very comprehensive review on the genes affecting clinical expression of SLE. Finally, Jönsen and collaborators prepared a review on the importance of environmental factors. Still much is needed to understand how genes interact with environment in causing lupus. This group of reviews is just a taste of the many questions that we have and that we want to answer as we continue in the gene identification path that lies ahead.