Which among the following karyotypes is characteristic of Klinefelter’s syndrome?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → XXY
Klinefelter’s syndrome is a chromosomal disorder caused by one extra X chromosome in a male. The person has 44 autosomes with XXY, that is 47 chromosomes in all (the book writes it as 47, XXY). The person develops as a male but some feminine features, such as breast development, also appear, and he is sterile. A related sex-chromosome disorder is Turner’s syndrome, where one X is missing in a female (45 with X0).
NCERT Extract:
Chromosomal Disorders – “… Klinefelter’s Syndrome : This genetic disorder is also caused due to the presence of an additional copy of X-chromosome resulting into a karyotype of 47, XXY. Such an individual has overall masculine development, however, the feminine development (development of breast, i.e., Gynaecomastia) is also expressed (Figure 4.17 a). Such individuals are sterile.”