Which of the following is a syndrome that is marked by an atypical sex chromosome complement?
A Prader-Willi syndrome
B Fragile X syndrome
C Down syndrome
D Klinefelter’s syndrome
The correct answer and explanation is:
The correct answer is D) Klinefelter’s syndrome.
Klinefelter’s syndrome is a genetic condition in males caused by the presence of one or more extra X chromosomes, resulting in a typical karyotype of 47,XXY instead of the usual 46,XY. It is characterized by an atypical sex chromosome complement, where individuals have an additional X chromosome. This syndrome occurs in approximately 1 in 500 to 1,000 male births.
The extra X chromosome in Klinefelter’s syndrome affects physical and cognitive development. Common symptoms include taller stature, reduced muscle mass, and less facial and body hair. These individuals may also experience mild developmental delays, learning difficulties, and speech and language issues. The condition can affect fertility, as men with Klinefelter’s syndrome often have low testosterone levels, leading to hypogonadism and reduced sperm production.
Klinefelter’s syndrome is typically diagnosed through chromosomal analysis, where the presence of an additional X chromosome can be identified. Early diagnosis is important for managing the condition, as hormone replacement therapy (such as testosterone) can help address some of the physical symptoms and improve quality of life. Educational support and speech therapy may also be beneficial for individuals with developmental delays.
It is important to note that Klinefelter’s syndrome does not cause a profound cognitive disability, and many individuals with the condition lead successful and productive lives. In fact, some may not be diagnosed until adulthood, when fertility issues or other symptoms lead to genetic testing. The syndrome highlights how variations in the sex chromosomes can have significant effects on development and health.