<unk> y is caused by an extra set of chromosomes.<unk> y can result from either two sperm fertilizing one egg (polyspermy) (60%) or from one sperm fertilizing an egg with two copies of every chromosome (40%). These are otherwise known as diandric fertilization and digynic fertilization. Pregnancies caused by digynic fertilization are more likely to end right before a baby is due for full term. Pregnancies caused by diandric fertilization result in a miscarriage towards the first trimester. Another factor known as a partial mole pregnancy can cause<unk> y. It is known to cause early termination, cancer, and even a second molar pregnancy.
Triploid syndrome
XX male syndrome
XXXY syndrome
XXXXY syndrome
Microdeletion syndrome
Chromosome instability syndrome
XXYY syndrome
XYY syndrome