How Can Genetic Screening Help You In Planning for a Baby?
Since the early 1900s, when the link between certain diseases and chromosomes was first established, the medical world has looked to genetics when attempting to diagnose, treat, and prevent a wide range of serious inherited conditions. Here we look at the beginnings of genetic screening, which diseases it can detect, and the pivotal role genetic testing plays in family planning today.
How did genetic testing begin?
Genetic tests were first developed during the 1950s that were capable of testing for Down syndrome, Duchenne muscular dystrophy, and cystic fibrosis. At that time, medical practitioners carried out diagnostic testing on newborns for conditions like phenylketonuria so that early interventions could be made and treatments administered to ensure the best possible outcome for affected individuals.
Today, genetic testing can detect over 2,000 conditions. Pregnant women the world over undergo genetic screening as a matter of course in many countries to assess the risk of potential children inheriting a genetic disorder. Pre-pregnancy genetic carrier screening is becoming an increasingly popular option in family planning. It allows prospective parents to assess the potential risk of them passing on a disorder ahead of time, enabling them to make informed choices and take preventative measures.
What are the most common genetic disorders?
Experts today recognize over 4,000 genetic disorders affecting an estimated 4 percent of children. Some genetic conditions are symptomatic at birth, whereas others become apparent at different stages in childhood. Occasionally, symptoms are delayed until adulthood. Here we take a look at some of the most prevalent genetic disorders.
Sickle Cell Anemia
Sickle cell anemia is a disorder that affects the blood. Genetic anomalies cause blood cells to change shape when stressed, resulting in defective hemoglobin molecules. They give up their oxygen and form long, rod-shaped clusters which harden in the sickle shape that earns the disease its name.
Whereas healthy red blood cells pass easily through capillaries, sickle-shaped red blood cells get stuck and build up, causing blockages and damaging tissue in organs. Because sickle cells die after just 20 days, as opposed to normal red blood cells which can last for up to 120, they also do not generate quickly enough, leaving the blood short of red cells, causing anemia.
Sickle cell anemia is more prevalent in those whose ethnic origins lie in Sub-Saharan Africa. A higher incidence also occurs in Central and South American and Indian communities. The disease affects approximately 1 in 500 newborns of African descent.
Thalassaemia
Thalassaemia is a genetic disorder that affects the blood. People with Thalassaemia present an error or absence in the genes responsible for producing hemoglobin, a protein necessary for the normal function of red blood cells. Thalassaemia can range in severity depending upon the genes affected.
Thalassaemia is one of the most widespread genetic disorders. It is most common in regions where malaria is common. In Mediterranean countries, government-led control programs have led to an 80 to 100 percent reduction of incidence of the disease in newborns.
Hemophilia
Hemophilia is another genetic disease that affects the blood. Here, a genetic fault results in a partial or total lack of clotting agent. People with hemophilia are susceptible to excessive bleeding, which can be spontaneous and internal. Hemophilia is a sex-linked hereditary condition that is more common in males. It occurs worldwide in all racial groups.
Cystic Fibrosis
Cystic fibrosis affects the digestive, respiratory and reproductive systems. People with this disorder inherit two faulty genes, i.e. one from each parent. In this disease, a genetic fault causes the body to produce a thick mucus that can obstruct the lungs and cause fatal infections. Cystic fibrosis affects an estimated 1/3,500 newborns in the US.
Tay-Sachs Disease
Tay-Sachs disease is a genetic disorder involving the overproduction of Ganglioside GM2, a fatty material that collects in the brain’s nerve cells. The condition can lead to blindness, paralysis, psychoses, dementia, and death.
The onset of degradation usually occurs in fetal development though symptoms may not appear until the age of 6 months. Tay-Sachs disease is prevalent in the Ashkenazi Jewish community. It is estimated that 1/27 Jews in the US is a carrier. In the non-Jewish US community, the carrier rate is approximately 1/250.
How can I avoid passing a genetic disorder on to my child?
The first step is assessing your risk by undergoing genetic screening. By being proactive and opting for genetic screening pre-pregnancy, prospective parents maximize the odds that their baby will be born symptom-free. Prospective parents may opt for genetic testing because their family history or ethnic origin indicates a potential risk, or they may just want peace of mind.
Even if medical practitioners detect a high degree of risk of a particular disorder, there are options for parents to mitigate that risk and still have biological children. Breakthroughs in IVF allow screening of the embryo prior to implantation, thus eliminating risk of passing on the genetic condition. It is in this way that genetic screening gives hope to families and medical practitioners the world over, potentially leading to the elimination of serious, and often life-threatening, genetic conditions.
