whyTestGenetics
What is the point of genetic testing?
By Antonie Kline, M.D., USA CdLS Foundation Medical Director
What is the point of genetic testing? Once you have received the results of genetic testing, what do you do with the information? How do you know if it will be helpful? What does it all mean?
When you have a child with Cornelia de Lange Syndrome (CdLS), these are all questions to ponder, ideally with a geneticist or genetic counselor to help answer them.
Genetic testing for a condition that is clinically diagnosed, like CdLS, can be helpful in a number of ways: clarification of diagnosis, further indication to obtain additional studies or additional testing, prenatal diagnosis for future children (to the couple, the individual or the siblings), and enrollment in the future clinical trials for treatments or medications.
Testing is expensive, may not be covered by insurance, and can result in vague and unsatisfying answers, so you do not want to embark upon it without careful thought. Although we are not even close to the point of carrying out clinical trials in CdLS, we hope that eventually we will be. And to enroll anyone for clinical trials, a diagnostic “marker” will be needed.
There are five known CdLS genes—NIPBL, SMC1A, SMC3, HDAC8 and RAD21—and different types of testing on those genes (e.g., sequencing, deletion/ duplication testing). It may be difficult to know if the correct test has been sent or if adequate testing has been completed. There are several companies that advertise testing for CdLS, but that testing may look for absence of the entire gene, which may be lethal before birth, and thus not even relevant.
We have heard from multiple families with children with CdLS who have started the quest for diagnosis and have had difficulties, such as missing results, incorrect interpretation and faulty conclusions. That is the point at which meeting with a genetic professional can be helpful. In addition to facilitating the actual testing sample, the professional can track down results, explain them and clarify the implications.
Overall, genetic testing can be mired in difficulties, so we would encourage all parents to seek genetic help prior to any sample being sent and, most importantly, upon receipt of results.
Testing is available at the following locations in the USA:
- Children’s Hospital of Philadelphia
- The CHOP research lab will soon have screening available for the five known CdLS genes. The research team also has a particular interest in individuals who have a diagnosis of CdLS but have had negative testing for the five genes.
Sarah Noon, M.S., (215) 590‐4248; noons@email.chop.edu.
- University of Chicago Genetic Services Laboratories
- Clinical lab providing testing for all five known genes.
(888) UC-GENES; ctan@bsd.uchicago.edu.
- Courtagen
- Commercial lab providing testing for all five known CdLS genes as part of their neurodevelopment disorder panel. Financial assistance is available to qualified families.
877.395.7608; com.
- GeneDx
- Commercial lab testing for NIPBL and SMC1A.
301- 519-2100; com.
