Autoimmune lymphoproliferative syndrome

Autoimmune lymphoproliferative syndrome (ALPS) is a disorder in which the body cannot properly regulate the number of immune system cells (lymphocytes). This results in the overproduction of lymphocytes, which build up and cause enlargement of the lymph nodes, liver and spleen. Affected individuals have an increased risk of developing cancer of the immune system cells (lymphoma) and may be at increased risk for other cancers. They can also have a variety of autoimmune disorders, most of which damage the blood cells. Some of the autoimmune disorders associated with ALPS can also damage the kidneys, liver, eyes, nerves, or connective tissues. Other signs and symptoms may include skin rashes, panniculitis, arthritis, inflammation of blood vessels (vasculitis), mouth sores, premature ovarian failure, and the development of neurological damage.

ALPS is caused by mutations in the FAS gene in about 75% of cases. It is usually inherited in an autosomal dominant manner, although a small number of cases are inherited in an autosomal recessive manner. Some cases are also believed to arise from a mutation in the lymphocytes that is not inherited, but instead occurs during the course of an individual's lifetime. This type of alteration is called a somatic mutation. Treatment may include steroids or other medications, blood transfusions, and/or splenectomy depending on the severity of the disorder.