What does genetic testing involve?
A blood sample is taken from the patient’s vein in a standard blood test. Specialized laboratory techniques are then used to examine the DNA from the blood cells to identify amyloidogenic mutations (abnormalities) in the TTR gene.
Where does genetic testing take place?
Currently the test in not available in Jordan. Samples are sent to a laboratory in Germany. The results are generally available after about 4 weeks
When is genetic testing used?
If ATTR amyloid fibrils are detected in tissue biopsy, then genetic testing can distinguish between hereditary and wild type ATTR amyloidosis. If a TTR gene mutation is detected, then the diagnosis is hereditary ATTR amyloidosis. If there is no TTR gene mutation, then the diagnosis is wild type ATTR amyloidosis (a non-hereditary condition). Symptoms and treatment are the same for these two conditions, but genetic testing can help us to learn more about the disease so that we may be better able to treat patients.
Genetic testing involves examination of the DNA from the patient’s cells. These techniques can identify amyloidogenic mutations (abnormalities) in the TTR gene. There are over 100 known mutations in the TTR gene, and different mutations lead to different types of disease. The precise mutation identified may provide information about the likely clinical course. For example, the most common mutation worldwide, the Val30Met mutation often leads to amyloid deposits just in the nerves, not in the heart. In contrast, the Val122lle mutation usually leads to amyloid deposits predominantly in the heart, and only occasionally affects the nerves. In wild-type ATTR amyloidosis, amyloid fibril analysis detects ‘wild-type’ ATTR protein and genetic testing will not detect any abnormalities in the TTR gene. Genetic testing in a healthy person without symptoms can provide information on whether the mutation is present but cannot predict whether the person will go on to develop amyloidosis.