Question

In Klinefelter's syndrome, the sex chromosome compliment is :

• A. 22 A + XXY
• B. 22 A + XO
• C. 22A + XY
• D. 22 A + XX

Answer 1

Answer: (A)

Klinefelter's syndrome is a human sex abnormality, arises due to non-disjunction of sex chromosomes during meiosis. It is characterised by the chromosome number. $2n=47,$ the chromosomal formula is $\text{44}\text{A}\text{+}\text{XXY}\text{.}$ Klinefelter's syndrome is a male in general appearance; testes are underdeveloped, enlarged breast (gyneco mastia), Mentally defective and abnormally tall. Mental retardation increases with X complement. The karyotypes of extreme Klinefelter's syndrome are $\text{44}\text{A}\text{+}\text{XXXY}\text{.}$ $\text{44}\text{A}\text{+}\text{XXXXY,}$ $\text{44}\text{A}\text{+}\text{XXXYY,}$ etc. In Turner syndrome, chromosome number is $2n=45.$ The chromosomal formula is $\text{44}\text{A}\text{+}\text{XO}\text{.}$ She is a sterile female. $\text{22}\text{A}\text{+XY}$ is chromosome constitution of normal male individuals which are heterogametic. $\text{22}\text{A}\text{+XX}$ is chromosome constitution of normal female individuals, are homogameric.