By Dr. Mark D. Johnson
I am often asked by my patients why I recommend that they consider genetic carrier screening for certain genetic diseases, even when they don’t have a family history of any known genetic diseases. In my last post, I shared with you the experience of one couple that came to me 6 years ago. That story is an example of the importance of genetic carrier testing.
Each year, thousands of children are born with genetic diseases. These children are born to parents who have no family history of genetic diseases. How does this happen?
All of us have imperfections and alterations in our genes known as mutations. In fact, each person is estimated to be a carrier of several recessive gene mutations. In the majority of couples, the mutations are not in the same genes. However, for some couples, like my patients Christine and John, the mutations are in the same critical genes, placing the couple at a 25% risk for having a child with a genetic disease. Typically, as with Christine and John, the carriers are healthy individuals with no prior family history of the genetic disease. And like Christine and John, most people do not know they are carriers for genetic diseases until they have a child born with the disease.An important part of family planning is being informed about your genetic testing options prior to or during pregnancy. Genetic carrier screening before conception can help you understand your risk of having a child with a genetic disease. The earlier you know your carrier status, the more options you have as a couple before a pregnancy is established.
There are options for couples determined to be carriers for recessive mutations that place them at an increased risk of having a child with a genetic disease, like Christine and John. Preimplantation genetic diagnosis (PGD) is one possible option. Preimplantation genetic diagnosis can be performed for a majority of recessive genetic diseases in which the disease gene mutation has been identified. Preimplantation genetic diagnosis screening of embryos for chromosome abnormalities involved in fetal abnormalities such as Down syndrome and miscarriages is also available.
The American College of Medical Genetics has recommended that every adult be offered genetic carrier testing before pregnancy for the relatively common genetic diseases: cystic fibrosis (CF) and spinal muscular atrophy (SMA). Here at Arizona Reproductive Medicine Specialists (ASRM) we offer all of our patients the opportunity to have carrier testing for these diseases, and if desired, to have carrier testing for more than 100 recessive diseases through a single DNA test. This test is the Universal Genetic Test by Counsyl.
As a reproductive endocrinologist and medical geneticist who is committed to assisting patients in their efforts to conceive healthy children, I strongly recommend that patients consider genetic carrier screening as an important step in the process of having healthy children. Please feel free to contact me for any questions about genetic carrier testing, preimplantation genetic diagnosis, or any reproductive genetic issues.
And may your hopes and prayers be answered.
Mark D. Johnson, M.D., FACOG, FACMG has practiced reproductive medicine and fertility in the Phoenix valley since 2000. He came to Phoenix with extensive professional experience in reproductive medicine. His background is unique in that he is both an experienced reproductive endocrinologist and infertility specialist and a clinical geneticist. He is Board Certified in Obstetrics and Gynecology with subspecialty Certification in Reproductive Endocrinology-Infertility and is Board Certified in the specialty of Medical Genetics. To make a consultation with Dr. Johnson at Arizona Reproductive Medicine Specialists, call (602) 281- 9032.
