What chromosome patterns would a person with Klinefelter's syndrome have?

A person with Klinefelter's syndrome typically has an extra X chromosome, which results in the chromosomal pattern XXY. This pattern arises due to nondisjunction during meiosis, where chromosomes fail to separate properly, leading to gametes that have an abnormal number of chromosomes. When an XXY sperm combines with a normal egg (which has one X chromosome), the resulting zygote will have two X chromosomes and one Y chromosome.

Individuals with Klinefelter's syndrome often exhibit physical characteristics such as taller stature, reduced muscle strength, and potential cognitive challenges, as well as impacts on fertility due to the presence of the additional X chromosome. This chromosomal arrangement is crucial for understanding the biological basis of the syndrome and how it affects development across the lifespan.