Klinefelter's syndrome is characterised by a karyotype of

Options

A. XYY
B. XO
C. XXX
D. XXY

Answer

D

Explanation

Klinefelter's 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 = 47` chromosomes `(44+XXY)`. Such persons are sterile males with undeveloped tests, mental retardationm, sparse body pair, long linbs and with some female characteristics such as enlarged breast i.e., gynaecomastia. It is considered that more that X chromosomes, greater is the mental defect. As the syndrome has two X chromosomes, one Barr body is seen in this case.