This partially allows the non-affected chromosome to balance out the other one. In males however, symptoms are much more severe because their one and only X chromosome will be non-functioning causing many problems. .
With newer technologies in science becoming more available, recently causes for the disorder Fragile X have been discovered. In 1991, scientists realized that fragile X was caused when a DNA mutation occurred disrupting the normal sequence in the FMR-1 region of the X chromosome. In particular, the "series of three particular nucleotides (CGG) in the DNA is greatly expanded beyond its normal size." Without fragile X people normally contain a CGG sequence that is repeated 5-50 times. People with the permutation have 50-200 repeated CGG's, while people with the full mutation have 200-800 repeats. However, it is not specifically the expansion of sequences that causes fragile X. Instead, the abnormality in the FMR-1 gene causes the person affected to fail to make the necessary fragile X mental retardation protein (FMRP) needed in specific cells. Without this protein needed for brain function, fragile X syndrome is triggered. .
The symptoms of fragile X are countless because there is such a wide range in which one can be affected. Not only that, but also different genders also have different symptoms, once again with wide ranges among them. One rule of thumb is that females will either have milder versions of males" characteristics or not have them at all. This ties back to the fact that females have two X chromosomes while males only have one. As it would be impossible to name all of the symptoms caused by fragile X, some of the major ones are as follows: "mental impairment; attention deficit and hyperactivity; anxiety and unstable mood; autistic-like behaviors; long face, large ears, flat feet; hyperextensible joints, especially fingers; and seizures (epilepsy) that affects about 25% of people with fragile X.