SNP Shot: Genomic Insights

Alpha thalassemia is a blood condition that lowers the body's ability to produce hemoglobin. Hemoglobin, found in red blood cells, is essential for transporting oxygen to all parts of the body.

Individuals with alpha thalassemia don't produce enough hemoglobin, leading to insufficient oxygen reaching their tissues. This also results in anemia (a shortage of red blood cells), which can manifest as pale skin, weakness, tiredness, and more significant health issues.

There are two main types of alpha thalassemia that can lead to health complications. Hemoglobin Bart hydrops fetalis syndrome (also known as Hb Bart syndrome or alpha thalassemia major) is the more severe form. HbH disease is the milder form.

Hb Bart syndrome is defined by hydrops fetalis, a buildup of excess fluid in the fetus before birth. Other symptoms can include severe anemia, an enlarged liver and spleen (hepatosplenomegaly), heart problems, and abnormalities in the urinary or reproductive systems. Due to these severe health issues, most infants with Hb Bart syndrome are stillborn or die shortly after birth without treatment. This syndrome can also cause serious pregnancy complications for the mother, such as preeclampsia (dangerously high blood pressure with swelling), premature delivery, and excessive bleeding.

HbH disease causes mild to moderate anemia, hepatosplenomegaly, and jaundice (yellowing of the skin and eyes). Symptoms of HbH disease typically appear in early childhood, and affected individuals often live into adulthood.

Inheritance:

Alpha thalassemia inheritance is complicated. Everyone inherits two alpha-globin alleles from each parent. If both parents are missing at least one alpha-globin allele, their children are at risk for developing Hb Bart syndrome, HbH disease, or alpha thalassemia trait. The exact risk depends on the number of missing alleles and which combination of HBA1 and HBA2 genes are affected.