Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome primarily affects males and is caused by problems with the immune system. The immune system normally protects the body from foreign invaders, such as bacteria and viruses, by recognizing and attacking these invaders and clearing them from the body. However, the immune system can malfunction and attack the body's own tissues and organs instead, which is known as autoimmunity. IPEX syndrome is characterized by the development of multiple autoimmune disorders in affected individuals. Although IPEX syndrome can affect many different areas of the body, autoimmune disorders involving the intestines, skin, and hormone-producing (endocrine) glands occur most often. IPEX syndrome can be life-threatening in early childhood.

Mutations in the FOXP3 gene cause IPEX syndrome. The protein produced from this gene is a transcription factor, which means that it attaches (binds) to specific regions of DNA and helps control the activity of particular genes. This protein is essential for the production and normal function of certain immune cells called regulatory T cells. Regulatory T cells play an important role in controlling immune responses and preventing autoimmune disorders. Mutations in the FOXP3 gene impair the normal function of regulatory T cells, making it difficult for the body to turn off immune responses when they are not needed. Normal body tissues and organs are attacked, causing the multiple autoimmune disorders that develop in people with IPEX syndrome.

IPEX syndrome is a rare disorder that affects an estimated 1 in 1.6 million people.

IPEX syndrome is inherited in an X-linked recessive pattern. The FOXP3 gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

Published Date: May 01, 2017
Published By: National Institutes of Health