What is Down’s syndrome ? Give its symptoms and cause. Why is it that the chances of having a child with Down’s syndrome increases if the age of the mother exceeds forty years ?
What is Down’s syndrome ? Give its symptoms and cause. Why is it that the chances of having a child with Down’s syndrome increases if the age of the mother exceeds forty years ?
Down's syndrome is a human genetic disorder caused due to trisomy of chromosome no. $21$ . Such individuals are aneuploid and have $47$ chromosomes $(2 \mathrm{n}+1)$. The symptoms include mental retardation, growth abnormalities, constantly open mouth, dwarfness etc. The reason for the disorder is the non-disjunction (failure to separate) of homologous chromosome of pair $21$ during meiotic division in the ovum. The chances of having a child with Down's syndrome increase with the age of the mother $(+40)$ because ova are present in females. Since their birth and therefore older cells are more prone to chromosomal non-disjunction because of various physico-chemical exposures during the mother's life-time.
Similar Questions
Select incorrect sentence for down's syndrome
Select incorrect sentence for down's syndrome
Which of the following statements are correct about Klinefelter's Syndrome?
$A$. This disorder was first described by Langdon Down $(1866)$.
$B$. Such an individual has overall masculine development. However, the feminine developement is also expressed.
$C$. The affected individual is short statured.
$D$. Physical, psychomotor and mental development is retarded.
$E$. Such individuals are sterile.
Choose the correct answer from the options given below:
Which of the following statements are correct about Klinefelter's Syndrome?
$A$. This disorder was first described by Langdon Down $(1866)$.
$B$. Such an individual has overall masculine development. However, the feminine developement is also expressed.
$C$. The affected individual is short statured.
$D$. Physical, psychomotor and mental development is retarded.
$E$. Such individuals are sterile.
Choose the correct answer from the options given below:
- [NEET 2023]
Down’s syndrome is caused by an extra copy of chromosome number $21$. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder
Down’s syndrome is caused by an extra copy of chromosome number $21$. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder
- [AIPMT 2003]
Define aneuploidy. How is it different from polyploidy ? Describe the individualsm having the following chromosomal abnormalities.
$(a)$ Trisomy of $21^{st}$ chromosome
$(b)$ $XXY$
$(c)$ $XO$
Define aneuploidy. How is it different from polyploidy ? Describe the individualsm having the following chromosomal abnormalities.
$(a)$ Trisomy of $21^{st}$ chromosome
$(b)$ $XXY$
$(c)$ $XO$
In Klinefelter's syndrome, what is generally the set of sex chromosome
In Klinefelter's syndrome, what is generally the set of sex chromosome
- [AIIMS 2000]