The Immunogenetics of Alopecia areata.

Alopecia areata (AA) is an autoimmune disease that targets the hair follicles (HF) and results in non-scarring hair loss. AA results from the collapse of the HF's immune privilege due to a combination of environmental and genetic factors that either change the local HF dynamics or dysregulate the central immune tolerance. Multiple genetic studies have attempted to identify AA susceptibility genes through candidate gene approaches and genome-wide analysis. These studies were able to show an association between AA and multiple immune-related genes such as those encoding cytokines, chemokines, molecules involved in regulatory T-cell functions, and adaptor molecules along with genes involved in autophagy, melanogenesis, and hair cycling pathways. This chapter aims to explore these genes and their contribution to the pathogenesis of the AA.