The best known example is Sickle Cell Disease, a serious hemoglobinopathy that causes anemia, susceptibility to infection, and organ damage in infants who inherit a gene for sickle hemoglobin from each parent. If a carrier of the disease has a child with another carrier, their child is at risk for inheriting the sickle cell gene from each parent and having the disease. Unless carriers of genetic hemoglobin disorders are identified prior to conception, they may not know that they can have a child with the disease. The decision to test for abnormal hemoglobins is usually based on the heritage of the parents. For example, Sickle Cell Disease is most common in people of African heritage.
Thalassemias are most common in people of Mediterranean, African, or Asian descent.
Medical and family histories that reveal other family members have a hemoglobin disease, or are known to be carriers, are reasons genetic testing should be considered.