The cause of 48,XXXY can be from non-disjunction in the paternal sperm or non-disjunction in the maternal oocyte. The most likely scenario for the existence of this aneuploidy is that each party (maternal and paternal) equally contributed to it, by the egg giving an XX and the sperm giving an XY. In the case where the sperm is the genetic cause of 48,XXXY<unk> , the sperm would have to contain two X chromosomes and one Y chromosome. This would be caused by two nondisjunction events in spermatogenesis, both meiosis I and meiosis II. The duplicated X chromosome in the sperm would have to fail to separate in both meiosis I and meiosis II for a sperm as well as the X and Y chromosomes would have to be in the same sperm. Then the XXY sperm would fertilize a normal oocyte to make a<unk>  zygote. In the case where the oocyte is the genetic cause of 48,XXXY<unk>  the oocyte would contain three X chromosome. This would be caused by two nondisjunction events during oogenesis. In meiosis I both sets of duplicated X chromosomes would have to be not separated. Then in meiosis II one set of X chromosomes would have to not separate and the other set would separate resulting in one oocyte with three X chromosomes. A normal sperm containing a Y chromosome would have to fertilize the XXX oocyte to make a<unk>  zygote. Mechanism The additional X chromosomes that are characteristic of this condition are associated with an androgen deficiency. This causes reduced or absent feedback inhibition of the pituitary gland, by elevating the gonadotropin levels.
XXXY syndrome
XYY syndrome
XX male syndrome
XYYY syndrome
Turner syndrome
XXYY syndrome
XYYYY syndrome
Klinefelter syndrome