A reduced number of red blood cells. Anemia occurs in persons with sickle cell disease because the sickled red cells do not live as long as normal red blood cells. The individual cannot make red blood cells fast enough to equal the loss of the sickled red blood cells.


An individual who possesses and can transmit the gene for a given disease but does not exhibit the disease.


Conditions present at birth.


The biological units that are passed from both parents to a child. Genes determine our various characteristics such as hair color and texture, eye and skin color, height, etc., including the kind of hemoglobin in the red blood cells.

Genetic Counseling

A communication process between health care provider and client that emphasizes providing accurate and up-to-date information about a genetic disorder in a sensitive and supportive, non-directive manner.


A protein in the red blood cell that carries oxygen from the lungs to other parts of the body and gives blood its red color.

Hemoglobin C Trait (AC)

The inheritance of one gene for normal hemoglobin (A), and one gene for hemoglobin (C). A person who has hemoglobin C Trait (AC) is a carrier of the hemoglobin C gene, and is not affected by the gene.

Hemoglobin Electrophoresis (e-lek-tro-for-e-sis)

A laboratory technique to determine the type of hemoglobin an individual has. When you pass an electric charge through a solution of hemoglobin, distinct hemoglobins move different distances, depending on their composition. This technique differentiates between normal hemoglobin (A) , sickle hemoglobin (S) and other different kinds of hemoglobin (such as C, D. E . etc.).

Hemoglobin F (Hemoglobin F)

The hemoglobin found in infants. Fetal hemoglobin decreases in quantity throughout the first year of life.

Hemoglobinopathy ( he-ma-glo-been-nop-a-the )

A term used to describe disorders caused by the presence of abnormal hemoglobin reproduction in the blood.


The transmission of physical and emotional traits and characteristics from parents to offspring.


To receive certain defined characteristics from a parent by transmission of the genes in the egg and sperm.


Yellowing of the skin and eyes, results from rapid breakdown of red blood cells.

Pain Event or Painful Episode (also known as sickle crisis)

Pain due to blockage of the blood vessels by sickled blood cells. Pain is most often felt in the arms, legs, back, and abdomen. The pain may last only a few hours or as long as a week or two. The pain may be mild or so severe that pain medicine is needed. The number of pain events a person has may vary greatly.

Red Blood Cells ( RBCs )

The blood cells that carry oxygen.

Sickle Cell Anemia (SS)

The most common form of sickle cell disease. Sickle cell anemia is the result of the inheritance of the gene for sickle hemoglobin (S) from both parents.

Sickle Cell Conditions

Sickle cell trait and the various types of sickle cell disease.

Sickle Cell Disease

An inherited disorder of the red blood cells in which anemia is present and sickle hemoglobin is produced. There are three common types of sickle cell disease in the United States: Hemoglobin SS or sickle cell anemia, Hemoglobin SC disease, and Hemoglobin Sickle beta-thalassemia.

Sickle Cell Trait (AS)

The inheritance of one gene for normal hemoglobin (A) and one gene for sickle hemoglobin (S) . A person who has sickle cell trait (AS) is a carrier of the sickle gene, does not have the disease, and is generally not affected by the sickle hemoglobin.

Sickled Cells

In persons with sickle cell disease, hemoglobin S in red blood cells stick to one another and cause the red cells to become crescent or sickle shaped. Sickled cells cannot pass easily through tiny blood vessels.

Thalassemia ( thal-as-seem-me-yah )

A group of inherited diseases of the blood that affect a person's ability to produce hemoglobin in their red blood cells.