What does being born with an extra Y chromosome mean?
XYY syndrome is a genetic condition that occurs when a male is born with an extra Y chromosome. Instead of having one X and one Y sex chromosome, those with XYY syndrome have one X and two Y chromosomes. Sex chromosome abnormalities like XYY syndrome are some of the most common chromosome abnormalities. (
What causes an extra Y chromosome?
An error in cell division called nondisjunction can result in sperm cells with an extra copy of the Y chromosome . If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra Y chromosome in each of the body’s cells.
What happens if you have two Y chromosomes?
When a sperm that has two Y chromosomes fertilizes an egg (which has an X chromosome), the resulting baby will be a male with two Y chromosomes and one X chromosome. It is also possible that a similar random event could occur very early in an embryo’s development.
What happens if you have 2 extra chromosomes?
Cells with two additional sets of chromosomes, for a total of 92 chromosomes, are called tetraploid. A condition in which every cell in the body has an extra set of chromosomes is not compatible with life.
What is XXYY syndrome?
XXYY syndrome is a sex chromosome anomaly in which males have an extra X and Y chromosome. Human cells usually contain two sex chromosomes, one from the mother and one from the father.
Who discovered XYY syndrome?
Dr. Harry Klinefelter discovered and defined the XXY syndrome in 1942, while helping male patients at Massachusetts General Hospital (Boston). The actual genetics were worked out by doctors later on, between 1956-1959.
How common is XYY syndrome?
XYY syndrome is listed as a ” rare disease ” by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that XYY syndrome, or a subtype of XYY syndrome, affects less than 200,000 people in the US population.
What is double Y syndrome?
Double-Y syndrome is a genetic mutation present in some males in the 22nd century. Specifically, it is a deformity of the X/Y chromosome pair, resulting in the YY pattern.
