Introduction and causes Klinefelter syndrome in newborns

Klinefelter syndrome is a fairly common genetic condition found in males only.

Many boys with Klinefelter syndrome- also known as XXY syndrome- have no signs or symptoms, and some don't even know they have it until later in life.

The XXY condition that causes  Klinefelter syndrome can't be changed, but medical treatment and working with therapists can help a boy's development and help lessen the effects of the conditions. Even without treatment, most boys with Klinefelter syndrome grow up to live productive, healthy lives.

CAUSES

Boys who have Klinefelter syndrome are born with it. It's also called XXY because they have an extra X chromosome in most or all of their cells.

Usually, a person has 46 chromosomes in each cell, divided into 23 pairs, which includes two sex chromosomes. Half of the chromosomes are inherited from the father and the other half from the mother. The chromosomes contain genes, which determine an individual's characteristics, such as eye color and height. Boys typically have one X chromosome and one Y chromosome, or XY, but boys with XXY syndrome have an extra X chromosome or XXY.

Klinefelter syndrome is not caused by anything the parents did or did not do. The disorder is a random error in cell division that happens when a parent's reproductive cells are being formed.

If one of these defective cells contributes to a successful pregnancy, the baby will have the XXY condition in some or all of his cells. Some boys will even have more than two X chromosomes (XXXY or XXXXY, for example), which increases the risk of severe symptoms and other health concerns.

When a boy is born with the XXY condition in only some of his cells, it's called mosaic Klinefelter syndrome. Often, boys and men with this condition can have milder signs and symptoms than there with the XXY condition.