What is Carrier Screening?

WHAT IS CARRIER SCREENING?

Over the last decade, access to preconception and prenatal genetic screening has become more common. For couples interested in starting a family, this means it’s easier to identify the risk of passing a severe disease on to a child or being a “carrier” for a genetic disease. Planning for a new child can be an exciting and anxious time for many parents.

At Baylor Genetics, we have been helping individuals make informed reproductive decisions for decades. We started with simple targeted testing for only a few diseases, and now offer GeneAware™, a carrier screen that assesses over 400 genes to let an individual know their risk of having a child with a genetic condition. We want you and your family to feel comfortable and knowledgeable before choosing to undergo carrier screening.

HISTORY OF CARRIER SCREENING

Carrier screening has not always been easily assessable, but as more genetic research has been performed, it has since evolved.

In 2017, the American College of Obstetricians and Gynecologists (ACOG) released a series of opinion papers on carrier screening in this modern age, which provided guidelines for providers and laboratories regarding carrier screening.1,2 While carrier screening has been available since the 1970s, early screening was very limited in scope.

“In the past, testing for less than 100 disease-causing variants [changes in DNA] were available to the public due to technological limitations and the cost, and was recommended only to certain ethnicities or for more targeted screening,” said Dr. Linyan Meng, Senior Division Director of NGS, Molecular, and CGI at Baylor Genetics. “Today, with technological advancements, expecting couples of all ethnicities are recommended to participate in genetic carrier screening in preparation for the birth of their child.”

One of the first carrier screening programs was designed to identify carriers of Tay-Sachs disease in the Ashkenazi Jewish community. Following the success of this screening program, which saw a 90 percent reduction in affected children, carrier screening was expanded to include several different diseases that affected individuals in the Ashkenazi Jewish community at a much higher rate than other ethnic groups.3

While ethnic-based carrier screening programs have proven successful, there are increasing numbers of multi-ethnic individuals worldwide. Therefore, carrier screening programs have had to evolve to meet the needs of a more diverse population.

WHAT DOES GENEAWARE™ OFFER?

The list of diseases recommended by ACOG for carrier screening panels has several diseases that are common in the Ashkenazi Jewish population, as well as diseases common in other populations, such as sickle cell anemia in the African American population, multiple types of alpha-thalassemia in the Asian population, or spinal muscular atrophy, a disease common in different ethnic groups.

At Baylor Genetics, we have designed a pan-ethnic panel that screens for diseases that have a high chance of being passed on to a couple’s child, regardless of ethnicity. Following the guidelines of the American College of Medical Genetics and Genomics (ACMG) and ACOG, our panel is designed to include a variety of genes associated with diseases seen in many ethnic populations, and diseases with high carrier frequencies in the general population. Criteria we considered for inclusion in GeneAware™, our comprehensive carrier screening, include some or all the following:

  • A carrier frequency of 1 in 100 or greater, which corresponds with a disease incidence of 1 in 40,000
  • Detection of challenging genes such as HBA, SMA1, and CYP21A2
  • Copy number variant analysis for increased detection rate
  • A well-defined phenotype (set of symptoms of a diseases)
  • A detrimental effect on the quality of life
  • A cause of mental or physical disability
  • Require surgical or medical intervention

HOW IS BAYLOR GENETICS’ CARRIER SCREENING TESTS DIFFERENT?

Baylor Genetics, GeneAware™ possesses one of the market’s largest genetic libraries of any carrier screening product and screens for over 400 genes.

With our comprehensive panel design, we screen individuals for a wide variety of diseases, including those in ACMG’s and ACOG’s recommendation, some of which have higher incidences in certain populations, but many with an incidence in the general population that meets the above criteria.

We also offer different GeneAware™ panels that vary in size (i.e., the number of genes screened). We understand the needs of individuals or reproductive partners are different. Some couples may want to screen for as many diseases as possible, others may wish for a more targeted approach.

“Carrier screening helps couples who are pregnant or planning a pregnancy understand the chance for their child to have a genetic disease. This knowledge helps them plan for their family either before or during pregnancy by providing options such as egg or sperm donation, adoption, prenatal testing, or natural conception for couples at risk, or by providing peace of mind from having a negative test result. Testing is always a choice, and each couple can make the choice that’s best for them,” said Christina Settler, Associate Vice President of Medical Affairs at Baylor Genetics.

At Baylor Genetics, we understand that reproductive genetic testing should be handled with precision and care. As carrier screening and other genetic tests continue to evolve, we promise that GeneAware™ will provide your family with accurate results and that our team of expert genetic counselors will provide you and your family with knowledgeable resources throughout your healthcare journey. Our GeneAware™ panels, made to identify several diseases are here to provide your family with the information you need to make informed decisions about your health.

 

References:
  1. Committee Opinion No. 690: Carrier Screening in the Age of Genomic Medicine. Obstet Gynecol. 2017;129(3):e35-e40. doi:10.1097/AOG.0000000000001951
  2. Committee Opinion No. 691: Carrier Screening for Genetic Conditions. Obstet Gynecol. 2017;129(3):e41-e55. doi:10.1097/AOG.0000000000001952.
  3. Kaback M, Lim-Steele J, Dabholkar D, Brown D, Levy N, Zeiger K. Tay-Sachs Disease— Carrier Screening, Prenatal Diagnosis, and the Molecular Era: An International Perspective, 1970 to 1993. JAMA. 1993;270(19):2307–2315. doi:10.1001/jama.1993.03510190063028
  4. Gregg, A.R., Aarabi, M., Klugman, S. et al. Screening for autosomal recessive and X-linked conditions during pregnancy and preconception: a practice resource of the American College of Medical Genetics and Genomics (ACMG). Genet Med 23, 1793–1806 (2021). https://doi.org/10.1038/s41436-021-01203-z
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