== 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.