Familial Chilblain Lupus - What Can We Learn from Type I Interferonopathies?

Purpose of Review Familial chilblain lupus belongs to the group of type I interferonopathies and is characterized by typical skin manifestations and acral ischaemia. This review aims to give an overview of clinical signs and the pathophysiological mechanisms. Recent Findings There are several mutations that can lead to this autosomal dominant disease. Most frequent is a mutation of the gene for TREX-1. However, as well cases of families with mutations in the SAMHD1 gene and, recently, with one for the gene that codes for the protein stimulator of interferon genes have been described. These genes are involved in the process of the detection of intracellular DNA, and their mutation results in an increased production of type I interferons and their gene products, resulting in auto-inflammation and auto-immunity. JAK inhibitors have been successfully used to treat this disorder. Summary Familial chilblain is a rare disorder with very distinct clinical signs. Its pathophysiological mechanism gives insight into the process of interferon-induced inflammation in auto-immune diseases.