1. 
   XXYY syndrome
   48,XXYY syndrome is a sex chromosome anomaly in which males have an extra X and Y chromosome. Human cells usually contain two sex chromosomes, one from the mother and one from the father. Usually, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). The appearance of ...
   Found op http://en.wikipedia.org/wiki/XXYY_syndrome
   
   

Tip: double click on a word to show its meaning.