Genetic Testing

Genetic testing is beginning to redefine the way that doctors look for pediatric retinoblastoma. While some types of genetic tests are already available, continuing research in the area of genetic testing is at a point where new breakthroughs are happening on a daily bases, and small changes are rapidly improving the way that doctors diagnose retinoblastoma. Earlier detection means that treatment can begin treatment earlier, increasing the chances of preserving eyesight and quality of life.

Types of Genetic Tests

There are different types of genetic tests that are used to detect hereditary retinoblastoma. Carrier tests, prenatal screening tests, and newborn screening tests can all be used to check for the gene mutation that is associated with hereditary retinoblastoma. Although the presence of the genetic mutation does not necessarily guarantee that the patient or child of the patient will have or does have retinoblastoma, the risk is much higher if the mutation is found. Genetic testing may also be done after retinoblastoma has been diagnosed to determine whether the retinoblastoma is hereditary or non-hereditary.

Carrier Tests

Carrier tests are tests that are conducted to determine whether a parent that has not had retinoblastoma carries the hereditary retinoblastoma gene mutation that may be passed to children. If a parent has this gene mutation, there is a 50 percent chance that the child will be born with the gene mutation. This type of testing can be used to test for a variety of other genetic predispositions in addition to hereditary retinoblastoma.

Prenatal Screening

Prenatal screening for retinoblastoma is most commonly used if a parent has the hereditary retinoblastoma gene mutation. This testing is conducted only at the discretion of the parents. If genetic tests reveal that the baby has the genetic mutation responsible for retinoblastoma, doctors may wish to induce labor early so that the child can begin treatment as early as possible. Again, this is at the parents’ discretion because the gene mutation does not cause retinoblastoma in 100 percent of cases.

Newborn Screening

A screening test may be conducted on a newborn if prenatal testing is not opted for. Genetic testing on newborns may also be used to test for many other heritable diseases, such as Down syndrome, sickle cell disorders, and cystic fibrosis. This type of genetic testing is becoming more common, and can help save lives through early detection of cancers and other life-threatening disorders.

Retinoblastoma Genetic Testing Procedure

To perform a genetic test for retinoblastoma, DNA must be obtained from the patient. The method for this varies depending on the type of test. If a patient has been diagnosed with retinoblastoma and the test is being conducted to determine the type, DNA may be carefully removed from the tumor that is behind the eye, or may be removed after surgery in some cases.

During screening for the carrier gene or newborn testing, DNA can be taken in the form of blood samples. During prenatal testing, amniotic fluid can be removed from around the fetus and testing for the genetic mutation. Once taken, these samples are examined closely for the mutation that causes retinoblastoma.