Alopecia areata is an organ-specific autoimmune disease targeting hair follicles. It causes nonscarring hair loss. The condition is most commonly seen as circular areas of hair loss but may sometimes be as extensive as to involve the whole scalp or whole body. Although some poor prognostic signs are defined, the course of the disease is unpredictable and the response to treatment can be variable. To date, there are neither preventive nor curative measures to deal with the condition. Causes of hair loss include aging, scalp inflammatory disorders, auto-immune disorder, and mechanical stress, which are known as senescent alopecia, cicatricial alopecia, alopecia areata, and traction alopecia, respectively. Focal hair loss, resulting secondarily from an underlying medical disorder, may either be non-scarring patchy hair loss, such as tinea captitis, alopecia areata, or may be a rare scarring type cicatricial alopecia, for example hair loss resulting from lupus erythematosus. Transcription factor 7-like 2 (T-cell specific, HMG-box), also known as TCF7L2 or TCF4, is a protein acting as a transcription factor that, in humans, is encoded by the TCF7L2 gene. The TCF7L2 gene is located on chromosome 10q25.2–q25.3, contains 19 exons. Genetic variations in the components of Wnt/β-catenin could greatly alter their adaptive mechanisms against an immunologic attack. Several studies indicate that the TCF7L2 gene variant is associated with Alopecia areata. Its contribution to disease pathogenesis could either be through a hair cycling defect or dendritic cell dysregulation

Transcription Factor 7-like 2, Alopecia Areata