SNP Shot: Genomic Insights

Wiskott-Aldrich syndrome (WAS) is a condition primarily affecting males, distinguished by three key features: immune deficiency (impaired immune system function), eczema (an inflammatory skin condition causing red, irritated patches), and difficulty forming blood clots.

A hallmark of WAS is microthrombocytopenia, meaning individuals have fewer and smaller platelets, which are crucial for blood clotting. This platelet abnormality is usually present from birth and can manifest as easy bruising, bloody diarrhea, or prolonged bleeding after minor injuries or nosebleeds. The condition can also result in small bleeds under the skin, appearing as purplish spots (purpura) or tiny red rashes (petechiae). Severe bleeding, particularly within the brain, can be life-threatening.

WAS also disrupts the function of white blood cells, the body's immune system cells. This leads to a higher risk of various immune and inflammatory disorders, with varying degrees of severity. Individuals with WAS are more susceptible to infections from bacteria, viruses, and fungi. They also face a greater risk of autoimmune diseases like rheumatoid arthritis, vasculitis, or hemolytic anemia, where the immune system mistakenly attacks the body's own tissues and organs. Furthermore, the likelihood of developing certain cancers, such as lymphoma (cancer of the immune system cells), is increased in those with WAS.

WAS is sometimes grouped with two other related disorders, X-linked thrombocytopenia and severe congenital neutropenia, due to their overlapping symptoms and shared genetic origin.

Inheritance:

WAS follows an X-linked inheritance pattern. This means the mutated gene responsible for the condition resides on the X chromosome, one of the two sex chromosomes. Males, possessing only one X chromosome, will develop the condition if that single copy of the gene is mutated. Females, with two X chromosomes, may experience milder symptoms or no symptoms at all if only one copy of the gene is affected. Importantly, fathers with an X-linked trait cannot pass it on to their sons.