The Aire gene, which stands for Autoimmune Regulator, plays a crucial role in the immune system. It is primarily responsible for the expression of tissue-specific antigens in the thymus, promoting the deletion of self-reactive T cells and thereby preventing autoimmune diseases. Mutations in the Aire gene can lead to a condition known as Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED), a rare autoimmune disorder.