What are the early warning signs or symptoms of Autoimmune Lymphoproliferative Syndrome (ALPS) that I should be aware of?

The most common early warning signs of ALPS, caused by FAS gene mutations, involve an abnormal accumulation of immune cells (lymphocytes). This often leads to enlarged lymph nodes (lymphadenopathy), an enlarged spleen (splenomegaly), and sometimes an enlarged liver (hepatomegaly). These enlargements can be persistent and may not be associated with an infection. Other signs can include easy bruising or bleeding, anemia, and recurrent infections. Autoimmune symptoms, where the immune system attacks healthy body tissues, such as autoimmune hemolytic anemia or immune thrombocytopenia, can also be early indicators.

FAS gene

The FAS gene provides instructions for a protein that initiates apoptosis, a critical process for removing unneeded or damaged cells from the body.

Normal Function

The FAS gene provides instructions for making a protein that is involved in cell signaling. Three FAS proteins group together to form a structure called a trimer, which then interacts with other molecules to perform its signaling function. This signaling initiates a process called a caspase cascade. The caspase cascade is a series of steps that results in the self-destruction of cells (apoptosis) when they are not needed.

Health Conditions Related to Genetic Changes

Autoimmune lymphoproliferative syndrome

At least 115 mutations in the FAS gene have been identified in people with a disorder of the immune system called autoimmune lymphoproliferative syndrome (ALPS). ALPS is characterized by the production of an abnormally large number of immune system cells (lymphocytes), resulting in enlargement of the lymph nodes (lymphadenopathy), the liver (hepatomegaly), and the spleen (splenomegaly).

When the immune system is activated to fight an infection, large numbers of lymphocytes are produced. Normally, these lymphocytes undergo apoptosis when they are no longer required.
FAS gene mutations lead to an abnormal trimer that interferes with the initiation of apoptosis.
As a result, excess lymphocytes accumulate in the body's tissues and organs and often begin attacking them, leading to autoimmune disorders.
Interference with apoptosis allows cells to multiply without control, leading to the lymphomas that occur in people with this disorder.

Cancers

Studies have associated certain FAS gene variations with an increased risk of developing cancer, including cancers of the lung, breast, and esophagus. Researchers believe that these variations may affect the signaling that initiates apoptosis, increasing the risk that cells will multiply out of control and result in cancer.

Other Names for This Gene

APO-1
apo-1 antigen
APO-1 cell surface antigen
apoptosis antigen 1
apoptosis-mediating surface antigen FAS
APT1
CD95
CD95 antigen
Fas (TNF receptor superfamily, member 6)
Fas AMA
Fas antigen
FAS1
FASLG receptor
TNFRSF6
TNR6_HUMAN
tumor necrosis factor receptor superfamily member 6