Question

In Klinefelter's syndrome, the sex chromosome compliment is

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

Answer 1

Answer: (A)

22A + XXY

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 44A + XXY. Klinefelter's syndrome is a male in general appearance; testes are underdeveloped, enlarged breast (gynaeco mastia), mentally defective and abnormally tall. Mental retardation increases with X complement. The karyotypes of extreme Klinefelter's syndrome are 44 A + XXXY, 44 A + XXXXY, 44 A + XXXYY, etc. In Turner syndrome, chromosome number is 2n = 45. The chromosomal formula is 44A+XO. She is a sterile female. 22 A + XY is chromosome constitution of normal male individuals which are heterogametic. 22 A + XX is chromosome constitution of normal female individuals, are homogenetic.