The Universal Genetic Test, manufactured by Counsyl, is a safe, inexpensive, non-invasive medical test that screens for dozens of serious genetic diseases, such as Cystic Fibrosis (CF), Spinal Muscular Atrophy (SMA), Sickle Cell, and Tay-Sachs disease (TSD). These genetic diseases cannot be cured, but couples who screen before having children, and test positive for the same condition, have a number of reproductive options available to them, including in vitro fertilization (IVF) coupled with preimplantation genetic diagnosis (PGD).
Prior to the development of the Counsyl Universal Genetic Test, most single gene genetic diseases would go untested because it has been cost-prohibitive for physicians to test for numerous genetic diseases ‘just to be sure’.
The Counsyl Universal Genetic Test is a saliva test for both men and women. It has been exhaustively validated and shown to be more than 99.9% accurate. Instead of testing for genetic diseases individually, Counsyl’s test can simultaneously test for over 100 diseases.
Genetic inheritance and disease
Individuals have two copies of every gene (one gene on each autosomal chromosome pair). The vast majority of gene pairs in the body are normal and function properly allowing for smooth protein synthesis and cell function. Some genes may malfunction due to a change in their DNA structure (genetic mutation).
Carriers are usually healthy individuals with little or no disease symptoms, who nevertheless have a mutant version of a recessive gene. For genetic diseases that are autosomal recessive, both copies of the gene must contain a mutation in order for an individual to be affected with the disease. A person with one normal gene copy and one mutant copy is known as a carrier.
What is genetic carrier testing?
Carrier testing is a method of checking an individual for certain mutations in their DNA that may not affect their health, but can cause their children to inherit a serious genetic disease. If both parents are “carriers” of the same gene mutation, their child has a significant 25 % chance of suffering from a serious genetic disease, like Cystic Fibrosis, Spinal Muscular Atrophy (SMA), Sickle Cell disease, Thalassemia, or Tay-Sachs disease and other Ashkenazi Jewish genetic disorders. Carrier testing for Fanconi anemia, Hurler Syndrome, Glycogen storage diseases, and over 100 other single gene disorders, is now available.
Testing positive as a carrier: How IVF/PGD can help
By undergoing in vitro fertilization (IVF) and genetically testing each Embryo-Preimplantation Genetic Diagnosis (PGD) for the single gene disorder, a couple can virtually eliminate their chances of having a genetically abnormal child.
By transferring only those embryos that are genetically normal or carriers, the couple can have a healthy baby. PGD is a safe and established procedure which allows carrier couples to prevent single gene genetic diseases. It has already been used to conceive thousands of healthy babies over the past two decades.
Autosomal recessive inheritance
Typically carriers will not develop any symptoms of the disease. However, the risk arises when two carriers conceive a child in the absence of carrier testing. Generally speaking, if both parents are carriers for the same gene mutation/disease, their children will have a 1 in 4 (25%) chance of having the disease!
X-linked recessive inheritance
The genes responsible for X-linked diseases are located on the X chromosome. For females, X-linked recessive conditions are similar to autosomal recessive: both copies of the gene must have a mutation in order for them to be affected. One mutated gene and one normal gene will make them a carrier of the disease.
Because males only have one X chromosome, if the gene on their single X chromosome has a mutation, he will develop the disease. Males cannot be carriers of an X-linked condition—they either have it or they don’t. Since only one gene mutation is needed, X-linked recessive conditions are much more common in males than in females.
Family and ethnic history
Some parents are aware of their increased risk of a given genetic disease due to a positive family history of an affected child. However, since the majority of genetic mutations are passed down quietly through the generations, more than 80% of children born with a preventable genetic illness lack a family history of that disease! As a result, the only way to know your carrier status for certain is through testing.
Each year hundreds of African American children are born with sickle-cell disease. Most thalassemia cases in the U.S. affect Asian Americans or those of Mediterranean descent. The Ashkenazi Jewish community is affected by a vastly disproportionate share of various genetic diseases.
The American College of Obstetricians and Gynecologists (ACOG) recommendations for preconception genetic carrier screening are as follows:
- CF carrier screening should be offered before conception or early in Pregnancy when both partners are Caucasian, European, or of Ashkenazi Jewish ethnicity. This carrier screening is often not performed due to high cost.
- Individuals of African, Southeast Asian, and Mediterranean descent are at increased risk for being carriers of hemoglobinopathies (sickle cell disease/thalassemias) and should be offered carrier screening. A complete blood count and hemoglobin electrophoresis are the appropriate laboratory tests for screening for hemoglobinopathies.
- Individuals of European Jewish Descent (Ashkenazi) should be offered carrier screening ideally before conception for TSD, Canavan disease, cystic fibrosis, and familial dysautonomia. Carrier screening is also available for mucolipidosis IV, Niemann-Pick Disease type A, Fanconi anemia group C, Bloom syndrome, and Gaucher’s disease. This carrier screening is often not performed due to extremely high cost. (Over $2000)
The American College of Medical Genetics (ACMG) has recommended that every adult of reproductive age be offered preconception carrier testing for cystic fibrosis and spinal muscular atrophy. As members of minority groups are at even greater risk for serious genetic disease — whether it be sickle cell disease in African Americans, Tay-Sachs in the Jewish community, or thalassemia in Asian Americans and those of Mediterranean descent — testing is indicated for virtually every population. The new medical consensus is that every adult should receive some genetic testing before pregnancy.
Based on the test’s cost-effectiveness, accuracy, and its benefits to patients, Fertility Centers of Illinois has begun offering the Counsyl Universal Genetic Test.