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A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by -
A
Turner syndrome
B
Down syndrome
C
Superfemaleness
D
Triploidy
Detailed Solution
Down's syndrome is caused by the presence of an additional copy of chromosome 21 (trisomy 21), so the total number of chromosomes becomes 47.
It results from non-disjunction of chromosome 21 during gamete formation, and its frequency increases with the age of the mother.
The affected individual is short with a small round head, a furrowed tongue and a partially open mouth, a characteristic palm crease, and retarded physical, psychomotor and mental development.
Turner's syndrome is 45, XO; superfemaleness is XXX (an extra X chromosome, not chromosome 21); triploidy is the presence of three complete sets of chromosomes (69).
So the woman is characterised by Down syndrome.
It results from non-disjunction of chromosome 21 during gamete formation, and its frequency increases with the age of the mother.
The affected individual is short with a small round head, a furrowed tongue and a partially open mouth, a characteristic palm crease, and retarded physical, psychomotor and mental development.
Turner's syndrome is 45, XO; superfemaleness is XXX (an extra X chromosome, not chromosome 21); triploidy is the presence of three complete sets of chromosomes (69).
So the woman is characterised by Down syndrome.