Who Does Rett Syndrome Affect?

One of every 10,000 to 15,000 infant girls will develop Rett syndrome. It affects all racial and ethnic groups worldwide. Rett syndrome is rarely seen in boys.

The chances of a family having a second child with Rett syndrome are less than one percent.

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.

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Have questions about Rett Syndrome?

Visit the My Child Without Limits support community and talk to parents, caregivers, and professionals about their experiences with Rett Syndrome.


Want to learn more about Rett Syndrome?

National Institute of Neurological Disorders and Stroke

International Rett Syndrome Foundation