Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is an inherited disorder characterized by a deficient immune system and significantly reduced number of platelets in the blood, which are used to help blood to clot. Typically platelet levels are reduced from birth, which often leads to mucosal bleeding and bloody diarrhea in affected infants, along with easy bruising and prolonged bleeding after trauma. Because of the immune system deficiency, affected males are susceptible to recurrent bacterial and viral infections which could lead to life-threatening complications. They are also at risk for autoimmune disorders and most will have mild to severe eczema. Affected individuals are also at increased risk for developing certain types of cancer. Survival rates have increased over the years as treatments have improved, however, without bone marrow transplantation, life expectancy is only into the early teens. Bone marrow transplant is the only known cure for WAS. WAS is caused by pathogenic variants in the WAS gene.

WAS is inherited in an X-linked recessive manner. This type of inheritance requires the presence of one copy of a pathogenic variant in the gene located on the X-chromosome for males to be affected. When the pathogenic variant is inherited from the unaffected carrier mother, the male child will have the genetic disease. There is a 50% chance that a baby will inherited the pathogenic variant from the mother; females who inherited the pathogenic variant will be carriers, males who inherited the pathogenic variant will be affected.

There are generally no signs or symptoms associated with being a female carrier for WAS. However, the risk to have a child affected with WAS is increased.

WAS is estimated to affect around 4 in 1,000,000 male newborns in the U.S.

The following websites may be informative: Genetic Home Reference: Wiskott-Aldrich syndrome (http://ghr.nlm.nih.gov/)

Gene Reviews: Wiskott-Aldrich syndrome (http://www.ncbi.nlm.nih.gov/books/NBK1116/) OMIM: [301000: WISKOTT-ALDRICH SYNDROME] (http://www.ncbi.nlm.nih.gov/omim)

• Full gene sequencing