About SCD Glossary

Glossary

Anemia

A decrease in the number of red blood cells, or hemoglobin, in the blood.

Chromosomes

Structure in the nucleus of the cell containing all the genes.

Fetal Hemoglobin (Hgb.F)

A kind of hemoglobin usually present during fetal (intrauterine) life, which has a different chemical structure from normal adult hemoglobin. After birth, the fetal hemoglobin in the red blood cells is gradually replaced by the adult type of hemoglobin, this process is usually complete during the first 6 months of life.

Gene

The ultimate unit of inheritance, carried by the chromosome. Genes determine our various characteristics such as hair texture, skin color, height, shape of nose, lips, 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.

Genetic Mutation

A change in hereditary characteristic due to a permanent change in a gene.

Hemoglobin

The chemical substance (an iron containing protein) of the red blood cell which carries oxygen to the tissues, and gives the cell its red color.

Hemoglobin C Trait (AC)

The inheritance of one gene for the usual 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

A laboratory technique to determine the type of hemoglobin the 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 usual hemoglobin (A), sickle hemoglobin (S) and many other different kinds of hemoglobin (such as C, D, E, etc.).

Inherit

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

Red Blood Cell

The cells in the circulation which contains hemoglobin.

Sickle Cell Anemia (SS)

An inherited disorder of the red blood cells in which the hemoglobin (the red oxygen carrying pigment of the cell) is different from the usual type. This unusual hemoglobin results in the production of unusually shaped cells, which do not survive the usual length of time in the blood circulation. Thus, anemia results. Sickle cell anemia is the result of the inheritance of the gene for sickle hemoglobin (S) from both parents.

Sickle Cell Disease

An inherited disorder of the red blood cells in which one gene is for sickle hemoglobin (S), and the other gene is for another unusual hemoglobin such as S, C, Thal. etc. The following are examples of sickle cell disease: SS, SC, SD, SßThal, etc.

Sickle Cell Trait (AS)

The inheritance of one gene for the usual 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, does not have painful episodes, and is generally not affected by the sickle hemoglobin.

Thalassemia (Thal)

An inherited disorder of the gene in the red blood cells which results in the impaired ability to produce hemoglobin.

Unusual Hemoglobins

In 1989, there where 489 unusual hemoglobins identified. The unusual hemoglobins most commonly seen (frequency in population greater than 1%) are hemoglobins: S (sickle), C, ßThal, E, and D (Punjab).