Genetic condition awaiting consideration - X-linked thrombocytopenia
X-linked thrombocytopenia is a rare genetic disorder caused by a mutation in the Wiskott Aldrich (WAS) gene. It causes a deficiency in the WAS syndrome protein, which in turn results in a low platelet count. This is part of a spectrum of WAS related disorders, of which Wiskott Aldrich syndrome OMIM #301000 is already licensed by the HFEA.
X-linked thrombocytopenia is inherited in an X-linked manner. This means for male embryos there is a 1 in 2 chance of the embryo being affected and for female embryos there is a 1 in 2 chance of the embryo being a carrier. Males who inherit the mutation will be affected but very few female carriers have medical problems.
The severity of symptoms cannot be reliably predicted and symptoms can vary between affected families and even within affected individuals in the same family.
The onset of the condition is usually in infancy, but some babies in-utero may display signs of anaemia.
Symptoms of the disorder range from:
- easy bruising and bleeding
- mild anaemia to severe haemorrhage or anaemia requiring long term blood transfusion therapy
- some affected individuals also have abnormal white blood cells which can result in life threatening bacterial and fungal infections, malignancies and autoimmune diseases such as eczema.
Bleeding, infection and malignancies have all been reported to cause death in a number of patients with X-linked thrombocytopenia.
The treatment of symptoms will involve medical and supportive care for blood/platelet transfusions, antibiotic therapy, stem cell transplantation, surgery for malignancies, immunosupressants for autoimmune disease and skin treatments including steroids for eczema. Some affected patients will require surgery for removal of the spleen which can in turn make them more prone to infection.
Overall the life span of males affected with X-linked thrombocytopenia is good, but the severity of disease related complications is high. For example they have a 1 in 20 chance of a cancer, 1 in 7 chance of serious bleeding, 1 in 14 chance of severe infection and 1 in 8 chance of an autoimmune disease.
Have your say on conditions awaiting consideration
If you have any feedback on the genetic conditions awaiting consideration by the HFEA, send us an email and we will discuss your comments at the next Licence Committee.
Email your feedback to: pgd@hfea.gov.uk
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Page last updated: 11 December 2012