Beta-thalassemia major and beta-thalassemia intermedia are usually inherited in an autosomal recessive manner, which means both copies of the HBBgene in each cell have mutations. The parents of a person with an autosomal recessive condition each carry one copy of the mutated gene and are referred to as carriers. When two carriers have children, each child has a 25% (1 in 4) chance to be affected, a 50% (1 in 2) chance to be a carrier like each parent, and a 25% (1 in 4) chance to be unaffected and not a carrier. Sometimes, people with only one HBB gene mutation in each cell (carriers) do have mild anemia. These people are said to have 'beta-thalassemia minor' or 'beta-thalassemia trait.'
In a small percentage of families, the condition is inherited in an autosomal dominant manner. In these cases, one mutated copy of the gene in each cell is enough to cause the signs and symptoms of beta-thalassemia.
Last updated: 6/18/2018
Can an individual with beta-thalassemia minor donate blood?
When an individual chooses to donate blood, he/she is typically examined and asked specific questions about his/her medical history (to make sure that donating blood isn't unsafe for the individual donating or for the recipient). During this process, the individual's hematocrit value (or hemoglobin level) is tested to make sure that the individual does not have anemia and is not likely to become anemic after donation. In order to donate blood, an individual's hemoglobin level must be at a specific level, which is established by the U.S. Food and Drug Administration (FDA). Usually, individuals with hemoglobin levels that are too low are temporarily not permitted to donate blood. A low hematocrit level is one of the most common reason people are temporarily disqualified or “deferred” from donating blood, but some donors can actually have anemia and still be eligible to donate.
People who have beta-thalassemia minor and are interested in donating blood should speak with their healthcare provider. Click here for more information about blood donation from the FDA.
Last updated: 12/5/2010
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please