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 == Trisomy of *sex* chromosomes? == 

 Would you define klinefelter syndrome as a trisomy? I haven't found any articles to prove the existence of the term ""trisomy of sex chromosomes"". 

 X and Y chromosomes are not identical, they're different chromosomes which belong in a group of ""sex chromosomes"". 

 Hence I think we cannot use the term ""trisomy of sex chromosomes"". Better term: Sex chromosome abnormalities."