Extra Y (Super Male Syndrome)

1. Extra Y (Super Male Syndrome) By: Mahdi Blaine

2. What is It? • Also known as XYY Syndrome, it is an aneuploidy of sex chromosomes which results in a male getting an extra Y chromosome. • This makes the total amount of chromosomes at 47 instead of 46. • It affects about 1 in 1000 male births.

3. History • During the 1960’s researcher did a study which found that a high number of men with XYY syndrome in prisons and mental institutes. • This is why it was originally called Super Male Syndrome, because the disorder was thought to have made men more aggressive and likely to commit crimes. • As the years went by, more unbiased studies were done which disproved all the previous research and showed that many were able to live normal lives.

4. Symptoms • Usually there are no distinct physical or medical abnormalities, which makes the use of genetic analysis be done. • During early childhood boys have a rapid growth spurt which is said to be caused by the extra gene since it also happens in 47,XXX, 47,XXY cases. • Boys have a greater risk for learning difficulties, and delayed speech and language skills and studies have been done that show that while their intelligence isn’t low, they are usually lower than their siblings. • Some males go their whole lives without knowing they have it. • Males that have it experience normal sexual maturity and most are fertile.

5. Causes • The disorder is not inherited, rather it is actually random event during the formation of sperm cells. • An error called nondisjunction happens in anaphase II of meiosis II. • This results in sperm cells with an extra Y chromosome. • This just leaves chance to decide if these sperm cells fertilize the egg first.