Does Fragile X Syndrome occur in males and females?

Fragile X syndrome (FXS) is an inherited disorder affecting intellectual, behavioral, and social development. It occurs in both males and females who have a full mutation of the FMR1 gene.

The FMR1 gene is on the X chromosome. Males have one X and one Y chromosome; females have two X chromosomes. In females with a full mutation, their other, normal X often compensates for the FMR1 mutation. That frequently results in milder symptoms of FXS. In males the Y chromosome cannot compensate for the effects of the Fragile X mutation.

Learn more:

• Request our free e-book, Fragile X 101 
• What is Fragile X syndrome? 
• Fragile X Info Series: Fragile X Syndrome An Overview for Families and Providers 
• Genetics & Inheritance