Question
True regarding Down syndrome is/are?
A. Associated with intellectual impairment
B. Abnormality in 21st chromosome
C. Maternal age > 35 is a risk factor
D. Paternal age > 35 is a risk factor
E. Most common type is translocation type
Show Answer
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Correct Answer » A:B:C
Explanation
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Ans. A, B & C
Cognitive/intellectual impairment, problems with thinking and learning, is common in people with Down syndrome and usually ranges from mild to moderate.
Only rarely is Down syndrome associated with severe cognitive impairment.
The most common cause (95%) of Down syndrome is trisomy 21.
There is an extra chromosome 21 (i.e. three 21 chromosomes) which is due to meiotic nondisjunction in ovum. The extra chromosome is of maternal origin.
The most important risk factor is advanced maternal age (> 35 years).
Advanced paternal age has no correlation with Down’s syndrome.
Roberston translocation accounts for 3% of cases of Down’s syndrome.
