Which condition is characterized by a 47 XXY chromosomal pattern?

The condition that is characterized by a 47 XXY chromosomal pattern is Klinefelter syndrome. This genetic condition occurs when a male has an extra X chromosome, resulting in the XXY configuration. The presence of this additional X chromosome can lead to a variety of physical and developmental differences, such as reduced testosterone levels, development of breast tissue, and potential learning difficulties.

Klinefelter syndrome typically manifests in males, as the presence of two X chromosomes, along with one Y chromosome, affects their sexual development and secondary sexual characteristics. This chromosomal pattern is distinct from the conditions listed in the other options, which involve different chromosomal abnormalities. For example, Turner syndrome involves a 45 X chromosomal structure, where females are typically missing one X chromosome. Down syndrome is associated with an extra chromosome 21, leading to a trisomy, while Patau syndrome is linked to an extra chromosome 13. Thus, Klinefelter syndrome is specifically defined by the 47 XXY pattern.