Fragile X syndrome chromosome analysis

Normal values:

In the laboratory a number of cells are evaluated and a percentage is established, comparing the number of abnormal cells to the number of normal cells. A normal result would indicate that less than 4% of the cells has a constricted section on the long arm of the X chromosome.

What abnormal results mean:

If more than 4% of the cells evaluated test positive for fragile X chromosomes, fragile X syndrome is indicated.