Sickle cell is not a sexually transmitted infection (STI). It is a genetic blood disorder that individuals are born with, passed down through inherited genes from their parents. This means it cannot be contracted through sexual contact or other acquired means. Understanding that sickle cell is inherited rather than acquired is important for grasping its true nature.
Understanding Sickle Cell
Sickle cell disease affects red blood cells, which carry oxygen throughout the body. Normally round and flexible, these cells in sickle cell become rigid, sticky, and crescent-shaped due to a genetic change. These abnormally shaped cells can block small blood vessels, restricting blood flow and preventing oxygen from reaching tissues and organs. This blockage leads to episodes of severe pain, often called sickle cell crises, and can damage organs such as the kidneys, liver, and spleen. The condition also results in chronic anemia because the sickle cells break down more quickly than healthy red blood cells.
Genetic Inheritance of Sickle Cell
Sickle cell disease is inherited in an autosomal recessive pattern. This means a child must inherit two copies of the altered gene, one from each parent, to develop the disease. The HBB gene provides instructions for making beta-globin, a part of hemoglobin, the protein in red blood cells that carries oxygen. If both parents carry one copy of the altered HBB gene (meaning they have sickle cell trait), there is a 25% chance with each pregnancy that their child will inherit two copies of the altered gene and develop sickle cell disease. There is also a 50% chance the child will inherit one altered gene and one normal gene, becoming a carrier (sickle cell trait), and a 25% chance the child will inherit two normal genes and not have the trait or disease.
Sickle Cell Trait vs. Sickle Cell Disease
Individuals with sickle cell trait have inherited only one copy of the altered gene. Generally, people with sickle cell trait do not experience the symptoms or health complications associated with sickle cell disease because they still produce sufficient normal hemoglobin. In contrast, individuals with sickle cell disease have inherited two copies of the altered gene, leading to the production of abnormal hemoglobin. This results in the characteristic sickle-shaped red blood cells and associated health problems, including chronic pain, anemia, and organ damage. While sickle cell trait usually does not impact a person’s lifespan, sickle cell disease is a serious illness that requires ongoing medical management.
Family Planning and Genetic Counseling
Family planning is an important consideration for individuals and couples. It is recommended that individuals, especially those with a family history of sickle cell or from populations where the trait is common, consider genetic testing to determine their carrier status. Knowing one’s status allows for informed decisions regarding reproductive options. Genetic counseling provides an opportunity to understand the risks of passing the gene to children and explore various reproductive choices. A genetic counselor can explain inheritance patterns, discuss testing options for both parents, and review possibilities such as in vitro fertilization with preimplantation genetic testing.