Question

Due to non-disjunction of chromosomes during spermatogenesis, sperms carry both sex chromosomes (22A + XY) and some sperms do not carry sex chromosome (22A + 0). If these sperms fertilize normal eggs (22A + X). What types of genetic disorders appear among the offspring ?

• A. Down's syndrome and Turner's syndrome
• B. Down's syndrome and Cri-du-chat syndrome
• C. Turner's syndrome and Klinefelter's syndrome
• D. Down's syndrome and Klinefelter's syndrome

Answer 1

Answer: (C)

Turner's syndrome and Klinefelter's syndrome

According to the question, fusion of an aneuploid sperm "22+ 0" and normal egg "22+X" will give rise to female child with chromosome composition "44+X". Absence of one X-chromosome causes Turner's Syndrome which is represented as 44 +XO. It is a female specific disorder. The affected females are sterile with rudimentary ovaries, underdeveloped breast, puffy fingers and short stature. They may not menstruate or ovulate. And fusion of an sperm with "22+ XY" and normal egg "22+X" will give rise to male child with chromosome composition "44+XXY". Presence of one extra copy of X-chromosome in males causes Klinefelter's syndrome. The affected individual has 44+ XXY /44+XXXY / 44+XXXXY chromosome. Presence of extra copy of X-chromosome produce some feminine characters in otherwise male individuals. Correct answer is option C.

Down's syndrome is trisomy-21, i.e., presence of chromosome 21 in three copies. It is an autosomal aneuploidy and does not affect any sexual characters. Loss of half of the short arm of chromosome 5 causes Cri-du-chat syndrome characterized by mewing like cry of newborn. Loss of half of the long arm of chromosome 5 causes severe developmental delay in newborn.