Carrier screening is a type of genetic testing that identifies people who carry one copy of a gene for certain inherited genetic disorders. Carriers typically do not experience health problems themselves, but they can pass the gene on to their children. If both parents are carriers of the same condition, there is a higher chance that their children will have the associated disorder.
They allows individuals and couples to understand their risks of having a child with certain conditions and to make informed family planning decisions. By identifying carriers, screening provides reproductive options like prenatal diagnosis, preimplantation genetic diagnosis (PGD), use of donor gametes, adoption, and choosing not to have children. This helps avoid or prepare for the birth of a child affected by one of these serious genetic disorders.
Disorders commonly included in its panels
Carrier screening panels usually test for several common conditions at once. The disorders most routinely included are cystic fibrosis, spinal muscular atrophy (SMA), Tay-Sachs disease, Canavan disease, Gaucher disease, beta-thalassemia, and fragile X syndrome.
Cystic fibrosis is the most common serious genetic disease among individuals of Northern European or Ashkenazi Jewish ancestry. It causes chronic lung infections and digestive problems. Around 1 in 25 individuals of Northern European descent are carriers.
SMA is a leading genetic cause of death in infancy. Carrier screening affects the motor neurons in the spinal cord, leading to muscle weakness and wasting. About 1 in 54 individuals are carriers for SMA.
Tay-Sachs disease and Canavan disease are both neurodegenerative conditions with onset in early childhood. Carriers are most common in Ashkenazi Jewish populations, affecting around 1 in 27 for Tay-Sachs and 1 in 40 for Canavan disease.
Gaucher disease results from a metabolic disorder that causes fatty deposits to build up in organs and bone marrow. It can range from mild to severe. Around 1 in 15 individuals of Ashkenazi Jewish descent are carriers.
Beta-thalassemia is a group of blood disorders causing anemia. Carriers are prevalent among people with Mediterranean, Middle Eastern, African, South or Southeast Asian ancestry.
Fragile X syndrome is the most common inherited form of intellectual disability and autism. Around 1 in 260-800 females and 1 in 500-1000 males carry a premutation of the FMR1 gene associated with fragile X syndrome.
Who should consider carrier screening?
Carrier screening is routinely offered to genetically diverse individuals, their partners, and close family members who plan to have children in the future. The following groups may benefit from carrier screening:
– Individuals of Ashkenazi Jewish, French Canadian, or Cajun ancestry have an increased likelihood of being carriers for certain conditions. For example, 1 in 4 people with Ashkenazi Jewish ancestry is a carrier for at least one disorder included in most screening panels.
– Anyone with a family history of a genetic condition should consider screening specifically for that disorder, even if their ethnic backgrounds are not typically associated with it. A family history increases the chance of being a carrier.
– All pregnant women, regardless of background, may choose expanded carrier screening as part of prenatal care. This identifies any disorders the baby may have a 1 in 4 chance of inheriting.
– Reproductive-age individuals who plan to have biological children someday would benefit from advance knowledge of any carrier statuses. It allows time to consider reproductive options before conception.
– Individuals considering using an egg, sperm, or embryo donor desire screening of the donor to avoid inherited conditions. Results influence which donor gametes are suitable.
The screening process
Following pre-test counseling, screening involves a simple blood draw or cheek swab sample from each individual or couple. The sample is sent to a specialized laboratory for analysis.
The most common screening panels check for dozens of conditions simultaneously using molecular genetic testing techniques like DNA analysis. Results are typically available within 2-4 weeks and reported as either negative (not a carrier) or positive (carrier) for each disorder included in the panel.
When both members of a couple screen negative, their child’s risk is very low or no increased chance. If one or both persons screen positive as carriers for the same condition, further counseling and testing options are discussed based on the actual risk level. Carrier combinations that pose higher risks often warrant prenatal diagnosis through amniocentesis, chorionic villus sampling or non-invasive prenatal testing.
Carrier screening provides reproductive autonomy
Identifying who carriers are empowers people to make proactive decisions about their future families. It removes uncertainty and allows carriers time to thoughtfully consider options based on their personal values and desires. Prenatal diagnosis, PGD, prevention through preimplantation genetic diagnosis using IVF and embryo biopsy or choosing to use donor gametes or adopt are all empowering choices it enables.
Knowing one’s carrier status before conception circumvents difficult situations like an affected pregnancy where termination is a consideration. It also prevents diagnosing affected infants after birth when management options are more limited. It is a safe, noninvasive form of preventive genetic testing that provides knowledge and reproductive control to help people reach their family planning goals.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
About Author – Alice Mutum
Alice Mutum is a seasoned senior content editor at Coherent Market Insights, leveraging extensive expertise gained from her previous role as a content writer. With seven years in content development, Alice masterfully employs SEO best practices and cutting-edge digital marketing strategies to craft high-ranking, impactful content. As an editor, she meticulously ensures flawless grammar and punctuation, precise data accuracy, and perfect alignment with audience needs in every research report. Alice’s dedication to excellence and her strategic approach to content make her an invaluable asset in the world of market insights. LinkedIn