Hemoglobin (Hb) is a protein in red blood cells that is responsible for carrying oxygen to the body. There are many hemoglobin types (this is not the same as a blood type). The most common hemoglobin in adults is hemoglobin A (Hb A). However, for infants, they initially have more fetal hemoglobin (Hb F) than Hb A.
A normal newborn screening hemoglobin result will show Hb F when an infant is first born. Hemoglobin F is completely replaced by Hb A when the infant is approximately 6 months old.
There are several genes involved in making a hemoglobin protein. There are four alpha globin genes and two beta globin genes. We inherit these genes from our parents. A change or mutation in any of the hemoglobin genes is what causes a hemoglobin disorder.
Hemoglobin Disorder symptoms are dependent on the number of mutated genes.
If only one beta gene or two alpha genes have a mutation, then a person is only a carrier of the disorder. This is referred to as a trait.
If two beta genes or three to four alpha genes are affected, then the person has the disorder.
Examples of Hemoglobin Traits & Disorders:
Beta Globin Genes
- Sickle Cell Disease
- Sickle Cell Trait
- Hemoglobin C, D, and E Disorders
- Hemoglobin Trait (C, D, E, and U)
Alpha Globin Genes