Ans. Assuming the target individual is a female -
# Presence
of an extra X-chromosome in females (47, XXX or X-trisomy) does not
exhibit any abnormality in around 90% of cases. It is because, the
extra X-chromosomes are randomly inactivated in form of Barr
bodies, such that each cell generally has only one functional copy
of the X-chromosome. Because each cell has a functional copy of
X-chromosome, the normal gene functions are expressed without any
adverse effects in around 90% cases.
# Genes on X-chromosome-
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APOO (encodes apolipoprotein )
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TRO (encodes Trophinin)
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SMS (encodes Spermine synthase enzyme)
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PLAC1 (encodes Placenta-specific protein 1)
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MIR660 (encodes protein MicroRNA 660)
