Why Does Rett Syndrome Mostly Affect Girls and Not Boys?
Girls have two X chromosomes in every cell. If they have Rett syndrome, some of the cells will use the defective gene. Other cells will use the healthy genes which will help to make up for the cells using the defective gene. However, boys only have one X chromosome in every cell. They lack the extra X chromosome that can protect their bodies from being completely overcome by the disorder. Therefore boys with the cell mutation that causes Rett syndrome often die before or shortly after birth.
