Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder characterized by an immune-mediated destruction of endocrine tissues, chronic candidiasis, and additional ectodermal disorders. In contrast to many other autoimmune diseases, APECED is associated with mutations of a single gene, designated autoimmune regulator (AIRE). To date, 45 different mutations of the AIRE gene have been identified and are distributed throughout the entire coding region. Several of the AIRE mutations predict the transcription and translation of a truncated protein, which may be nonfunctional. In contrast to the genetic background of APECED, in all of the autoimmune conditions typically associated with APECED the conclusive role of a single genetic locus capable of providing insight into the etiology of the disease has not been identified. Here we provide an overview of the current clinical and genetic features of APECED in comparison to the genetic background of the frequently associated disease components of APECED.