Wiskott Aldrich Syndrome is a genetic disorder that almost exclusively affects males. Because it is congenital, or present at birth, symptoms first appear very soon after birth to up to 1 year of age. Wiskott Aldrich is a rare syndrome, affecting only 1 to 10 per 1 million males, but it is a serious primary immunodeficiency disease.
The Genetics
Wiskott Aldrich Syndrome is caused by a mutated gene, known as the WAS gene, which is located on the short arm of the X chromosome. Males have one X and one Y chromosome and females have two X chromosomes. Since the mutation is rare and is recessive (meaning it is expressed only in the absence of a normal gene), only males are affected. For females to inherit the condition, both of their X chromosomes would have to exhibit the mutation, which is extremely unlikely.
Because the condition is inherited, there may be a known family history in the patient's brothers or maternal uncles. In small families, however, there may be no history because of the rare occurrence of the mutation.
Mode of Action
The mutation of the WAS gene affects the WAS protein (called WASP). The WASP is found in blood cells and immune cells, including T cells and B cells. This protein is involved in determining the cell's shape and ability to move. The mutation to the WAS gene impairs the WASP protein, which impairs the cell's ability to grow and divide. In addition, these cells have difficulty moving and attaching to other cells, which impairs the normal immune functions of the cells.
The impaired WAS protein function also affects platelet development, causing decreased size and number of platelets. Platelets are small fragments of cells that function in blood clotting.
Symptoms
Wiskott Aldrich Syndrome is an immunodeficiency disease. The most common symptoms include:
Microthrombocytopenia, or low platelet count, which can lead to excessive bruising and/or prolonged bleeding after minor trauma.
Eczema, an inflammatory skin disorder that is marked by red, irritated itchy skin.
Recurrent infections--bacterial, viral or fungal.
Diagnosis
For infants with unusual bleeding and bruising, a sample of blood should be taken. The best way to definitively diagnose Wiskott Aldrich Syndrome is by performing a blood platelet count and assessing the size of the platelets. Another test can determine if there is an absence or decrease in the WAS protein in the blood.
Complications
Patients with Wiskott Aldrich Syndrome are at risk of developing other conditions that may be life-threatening:
Autoimmune Disorders. Since the immune cells, including T and B cells (or lymphocytes) are affected, the body's immune system may react against itself. Several conditions could result, including vasculitis (blood vessel inflammation) and a type of anemia in which antibodies destroy red blood cells.
Malignancies. Most WAS-related malignancies involve B-lymphocytes, including leukemia and lymphoma.
Treatments
Patients with Wiskott Aldrich Syndrome will need to undergo continual monitoring and treatments. Because of increased bleeding, they may need to take iron supplements to defend against anemia. Since they are at increased risk for infections, antimicrobial treatments may be necessary. For some, a bone marrow transplant is necessary and can greatly increase life expectancy.
When Wiskott Aldrich Syndrome was discovered in 1937, the life expectancy was only 2 to 3 years. However advancements in diagnosis and treatments, especially the technology to perform bone marrow transplants, have greatly increased this expectancy, and many affected males live into adulthood.
Tags: Wiskott Aldrich, Aldrich Syndrome, Wiskott Aldrich Syndrome, blood cells, bone marrow, cells including, cells including cells