Carrier screening test: Who should consider it? Experts on its benefits

In an interview with HT Lifestyle, Dr Sangeeta Rodeo, Consultant-Gynecology and Obstetrics at Fortis Hospital in Mumbai, explained, “Couples should be guided and offered counselling for carrier screening testing before pregnancy, giving them timely information about their reproductive risks and receiving explanations about alternatives. Being a carrier of a genetic condition can depend on two factors: ethnicity and family history. As a result, carrier screening has traditionally been proposed for individuals/couples at risk of a specific disease based on risk factors like positive family history and high risk in certain ethnic groups.”

She elaborated, “Carrier screening is only available for a limited number of diseases, including Cystic Fibrosis, Fragile X Syndrome, Sickle Cell Disease and Tay–Sachs disease. As a routine, tests are done to rule out hemoglobinopathies such as Thalassemia and Sickle Cell disease during pregnancy. The husband is also offered testing if a patient is found to be a carrier. There is a 25 per cent that a child will have the disorder and get the gene from either of the parents if both parents are carriers of a recessive gene that can pass on the condition. Before getting pregnant, if an individual is found to be a carrier for a specific condition, then their partner should be offered testing. This will provide them with the relevant information so they can go for genetic counselling to know about the potential reproductive outcomes of their unborn child.”

Highlighting that concurrent screening of the couple can also be suggested for faster prenatal diagnostic evaluation, Dr Sangeeta Rodeo said, “If both partners are carriers of a genetic condition, genetic counselling should be considered. To decrease the risk of the offspring getting affected by the disorder, prenatal diagnosis and the use of advanced reproductive technologies should be discussed with parents and relevant experts. Thus, carrier screening gives you many options to prevent transmission to offspring.”

According to her, if a person has a carrier screening before they get pregnant, they have the following benefits:

• They can decide the course of their pregnancy and perform prenatal diagnostic tests to see if the fetus has the disorder.
• They can use in vitro fertilization (IVF) with donor eggs or sperm to get pregnant. This option allows the embryo to be tested before it is transferred to the uterus.
• They can choose not to get pregnant and go for adoption as an alternative.

Bringing his expertise to the same, Dr Shiva Murarka, Senior Scientist-Reproductive Genomics at Neuberg Centre for Genomic Medicine in Ahmadabad, said, “Carrier screening tests are a valuable tool that can provide important insights into the health of prospective parents and their future children. These tests are designed to identify if individuals carry genetic mutations that could potentially be passed on to their offspring. While carrier screening doesn't diagnose any condition in the person being tested, it helps couples understand the risk of having a child with a genetic disorder.”

He suggested, “Consider getting a carrier screening test if you're thinking about starting a family or expanding your family. It's especially recommended for couples who have a family history of certain genetic disorders. Even if you don't have a family history, carrier screening can still offer valuable information about your genetic makeup. If both partners are carriers of the same genetic mutation, there is a chance their child could inherit two copies of that mutation, leading to a genetic disorder. This is more common when both partners belong to the same ethnic group, as certain genetic conditions are more prevalent in specific populations.”

He concluded, “Remember, carrier screening isn't just for those with concerns; it's a proactive step towards ensuring the well-being of your future children. Advances in genetic testing have made it easier to identify potential risks and make informed decisions. Discussing carrier screening with your healthcare provider can help you make the best choices for your family's health. In essence, carrier screening offers peace of mind and the opportunity to make informed choices. It's a way to empower couples with knowledge about their genetic makeup, reducing uncertainty and allowing them to plan ahead. By taking this important step, couples can better prepare for a healthy and happy future for their family.”