Genes can be obtained from a blood or tissue sample. Researchers can separate DNA from the rest of the sample and test for the presence of disease-causing genes. Once a gene has been located, it is possible, in certain families, to perform tests on the genetic material found in blood and other cells to determine which members of the family have a retinal degeneration gene. Direct Testing Direct tests are much like any other medical blood tests in that they show whether or not a certain disease is present. A direct test requires that the gene and the specific mutation, the change that causes the disease, are known.
Researchers can then look for the disease-causing mutation.
If it is present, then the individual has the genetic disorder. If an individual with ADRP has a mutation, other family members can be tested for that mutation. Family members who are found to have the same mutation are likely to have ADRP also. If the individual with ADRP does not have any of the known mutations, the individual and his or her family might want to pursue indirect gene testing. Unaffected individuals with a family history of retinal degeneration and individuals who are affected but do not have a family history can also have direct tests for all the known gene mutations.