Question

An example for autosomal hyper aneuploidy is
A.Downs syndrome
B.Klinefelter's syndrome
C.Turner's syndrome
D.haemophilia

Answer 1

Hint: Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example for a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete seats of chromosomes. A cell with any number of complete chromosome sets is called a euploid cell.

Complete step by step answer:
Down’s syndrome is mainly caused due to an extra copy of chromosome 21 which is hyper aneuploidy of the autosomal chromosome. Aneuploidy is the presence of an abnormal number of chromosomes. The extra copy is formed due to nondisjunction of chromosomes during meiosis.
Additional information: An extra or missing chromosome is a common cause of some genetic disorders. Some cancer cells also have abnormal numbers of chromosomes. About 68% of human solid are aneuploid. Aneuploidy originates during cell division when the chromosomes do not separate properly between the two cells. Most cases of aneuploidy in the germline result in miscarriage, and the most common extra autosomal chromosomes among live births are X Y 21,18 and 13. Chromosomes abnormalities are detected in 1 to 160 live human births.

Hence the correct answer is option(A)

Note: Most cells in the human body have 23 pairs of chromosomes, or a total of 46 chromosomes. One copy of each pair is inherited from the mother and the other copy is inherited from the father. The first 22 pairs of chromosomes are numbered from 1 to 22, from largest to smallest. The 23rd pairs of chromosomes are the sex chromosomes. Normal females have two X chromosomes, while normal males have one X chromosome and one Y chromosome. The characteristics of the chromosomes in a cell as they are seen under a light microscope are called the karyotype.