Question

Klinefelters syndrome is characterised by a karyotype of

• A. XYY
• B. XO
• C. XXX
• D. XXY

Answer 1

The correct option is D XXY

Klinefelters syndrome occurs by the union of an abnormal XX egg and a normal Y sperm or a normal X egg and abnormal XY sperm. The individual has 2n = 41 chromosomes (44 + XXV). Such persons are sterile males with undeveloped testes, mental retardation, sparse body haii long limbs and with some female characteristics such as enlarged breast Le. gynaecomastia. It is considered that more the X chromosomes, greater is the mental defect. As the syndrome has two X chromosomes, one Barr body is seen in this case.

So, the correct answer is 'XXY'.