Triple X Syndrome
Tracie Emmerich
Professor Debbie Seale
Biology 101
TR, 8:30-11:30 am
3/6/2012
Triple X Syndrome
Triple X Syndrome is a sex chromosome abnormality in which there are three X chromosomes instead of the usual two found in most females. Triple X Syndrome is also known as Trisomy X, Triplo X Syndrome, and XXX Syndrome. The first published report of a woman with a karyotype with a 47, XXX was by Patricia A. Jacobs in 1959 at a hospital in Scotland. Most people have 46 chromosomes, occurring in 23 pairs. These chromosomes contain genes, which carry instructions that determine everything from your height to your eye color. One of these chromosome pairs determines your sex. You receive one sex chromosome from your mother and another from your father. Your mother can give you only an X chromosome, but your father can pass on an X or a Y chromosome. If you receive an X chromosome from your father, the XX pair makes you genetically a female. Females with Triple X syndrome have a third X chromosome. Triple X syndrome usually results from an error in the formation of a mother's egg cell or a father's sperm cell. Sometimes, triple X syndrome occurs as a result of an error early in the embryo's development. Although this condition is genetic, it's typically not inherited. Instead, what usually happens is that either the mother's egg cell or the father's sperm cell has not formed correctly, resulting in an extra X chromosome. This random error in egg or sperm cell division is called nondisjunction. Nondisjunction is a random event and is not caused by anything either of the baby’s parents did or by any medications they may have taken.
When the cause is a malformed egg cell or sperm cell, as is usually the case, all the body's cells have the extra chromosome. In the mosaic form, only some of the body's cells have the third X chromosome. Because only some cells contain the extra X chromosome, females with the mosaic form of triple X syndrome may have less severe symptoms.
Professor Debbie Seale
Biology 101
TR, 8:30-11:30 am
3/6/2012
Triple X Syndrome
Triple X Syndrome is a sex chromosome abnormality in which there are three X chromosomes instead of the usual two found in most females. Triple X Syndrome is also known as Trisomy X, Triplo X Syndrome, and XXX Syndrome. The first published report of a woman with a karyotype with a 47, XXX was by Patricia A. Jacobs in 1959 at a hospital in Scotland. Most people have 46 chromosomes, occurring in 23 pairs. These chromosomes contain genes, which carry instructions that determine everything from your height to your eye color. One of these chromosome pairs determines your sex. You receive one sex chromosome from your mother and another from your father. Your mother can give you only an X chromosome, but your father can pass on an X or a Y chromosome. If you receive an X chromosome from your father, the XX pair makes you genetically a female. Females with Triple X syndrome have a third X chromosome. Triple X syndrome usually results from an error in the formation of a mother's egg cell or a father's sperm cell. Sometimes, triple X syndrome occurs as a result of an error early in the embryo's development. Although this condition is genetic, it's typically not inherited. Instead, what usually happens is that either the mother's egg cell or the father's sperm cell has not formed correctly, resulting in an extra X chromosome. This random error in egg or sperm cell division is called nondisjunction. Nondisjunction is a random event and is not caused by anything either of the baby’s parents did or by any medications they may have taken.
When the cause is a malformed egg cell or sperm cell, as is usually the case, all the body's cells have the extra chromosome. In the mosaic form, only some of the body's cells have the third X chromosome. Because only some cells contain the extra X chromosome, females with the mosaic form of triple X syndrome may have less severe symptoms.