A new genetic test could make the diagnosis of hereditary angioedema easier. The test analyzes all the SERPING1 gene. According to the study published in the journal Gene, the new method identifies types 1 and 2 of the disease much better than traditional tests. For this reason, researchers recommend its use alongside traditional diagnostic methods.

Hereditary angioedema is a rare genetic disease that causes cutaneous and subcutaneous swelling. Type 1 angioedema is caused by low levels of the C1 protein, while type 2 is linked to a defective protein. Type 3 is the result of some mutations in the coagulant factor XII.
In the new study, researchers analyzed the DNA of a group of subjects possibly suffering from angioedema. The aim was to give a more precise diagnosis and to better understand the nature of the disease. Tests reported more than 450 mutations in the SERPING1 gene. The gene provides instructions for making the C1 inhibitor protein.

Genetic tests usually used for the diagnosis of the disease are long and unreliable. In 5-10% of cases they are not even able to detect SERPING1 mutations. In fact, traditional genetic tests do not cover the whole gene and skip regions that are not translated into proteins. Unfortunately, mutations may also be present in these regions. The new test then also analyzes the parts of the gene previously ignored.

The study authors validated the new test using 102 samples of DNA analyzed by traditional methods. They also used 115 samples with negative results and 95 samples taken from relatives of the patients. The new test identified the mutation at SERPING1 in 91 patients already diagnosed, but on which the traditional tests had not worked. Furthermore, they identified 15 entirely new mutations.
According to the study, the new genetic test is 98.96% reliable and has an accuracy of 99.35%. The false negative rate was very low.

Source: angioedemanews.com