DOCK8 deficiency is an immune disorder characterised by frequent respiratory and skin infections. DOCK8 is a protein that assists specific immune cells in moving through denser parts of the body, like the skin. When there is not enough DOCK8, these immune cells are unable to fight infections that live on the skin. People with DOCK8 deficiency also have an extremely high amount of a certain antibody called immunoglobulin E (IgE).
An antibody is a protein that fights foreign objects in the body. IgE is particularly responsible for fighting parasites and producing allergic reactions. There is also a certain type of white blood cell called an eosinophil that helps facilitate allergic reactions. Eosinophils are also produced in very high amounts in people with DOCK8 deficiency. It is unclear why people with a DOCK8 deficiency experience high levels of IgE and eosinophils.
Symptoms of DOCK8 deficiency include:
DOCK8 deficiency is caused by gene changes to the DOCK8 gene. The DOCK8 gene produces the DOCK8 protein, which is responsible for maintaining the structure of T cells, white blood cells that detect infection. The protein is also part of the pathway that helps B cells, white blood cells that kill infections, to mature. When the DOCK8 gene changes, or mutates, the DOCK8 protein is barely produced, and if it is, it is not functional.
Lack of functional DOCK8 protein leads to an inability of the immune system to function properly. Research shows that T cells that do not have the DOCK8 protein die quickly when they try to move through the skin, resulting in frequent infections on the skin. Additionally, the lack of mature B cells has been shown to lead to frequent respiratory infections.
The DOCK8 deficiency itself is inherited in what is called an autosomal recessive pattern. This means that a changed DOCK8 gene must be inherited from the mother and the father in order for someone to have DOCK8 deficiency. It is possible for someone to live a healthy life with just one changed DOCK8 gene.
The risk factor for DOCK8 deficiency is having a parent with DOCK8 deficiency. It is impossible to know without genetic testing if one or both parents has one mutated DOCK8 gene.
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Immunodeficiency Disease Medications
To diagnose DOCK8, your physician will order lab tests to look at the cell count of certain white blood cells. High IgE count, high eosinophil count, and low B-cell count are all indicators of a potential DOCK8 diagnosis and would prompt your doctor to offer protein analysis and genetic testing. Analysis of the amount of DOCK8 protein in your blood can be a helpful indicator of whether you have DOCK8 deficiency or not. However, genetic testing for DOCK8 is the only thing that can offer a definitive diagnosis.
Complications of DOCK8 deficiency include:
Treatment for DOCK8 involves frequent screening for development of any complications, preventative antibiotics, treatment of symptoms and infections, and bone marrow transplants. Bone marrow produces white blood cells, and a transplant gives DOCK8 patients the prospect of producing new, healthy white blood cells. Transplants are not without risks.