Fragile X Disease Essay

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Fragile X is a disease which severely influences the everyday lives of those affected by it. It is a disease which unfortunately limits an individual in several respects. Physical symptoms include an elongated face with larger than normal ears and feet. Additionally, the individual will have a difficult time interacting with others due to shyness and trouble with processing faces, thus encountering behavioral road blocks. Most importantly, the individual may have intellectual disabilities such as difficulty with memory, all a result of having Fragile X. Fragile X is the most common single gene which leads to autism and other intellectual disabilities. Fragile X is transmitted through DNA. Within the DNA, it has been found that the …show more content…
As previously stated, those with more than 30 repeated trinucleotides of CGG are likely to develop some form of Fragile X (often referred to as premutation), with those having over 200 repeats having the full syndrome (also known as a full mutation). All of the repeated trinucleotides are located within the promotor region of the FMR1 gene. The reason the FMR1 gene produces so little FMRP is due to a process called methylation. "Methylation is a process which inactivates a gene, and the larger number of repeats inactivates the gene. When the gene is inactivated, the cell may make little or none of the needed FMRP." (NICHD 2009). Figure 2: Normal promoter region VS. Elongated promoter region (NICHD 2009) Intriguingly enough, in certain cases, despite having 200+ CGG trinucleotide repeats within a FMR1 gene, it is still possible to be able to produce FMRP. One way this can be performed is by being born female. Males are born with an X and Y chromosome. Females however, are born with two X chromosomes. A female with Fragile X in one chromosome may not necessarily have Fragile X within the other chromosome. Within the female, certain cells may choose to activate one of the X chromosomes, and other cells may choose to activate the other X chromosome. Hence, even though there exists a Fragile X chromosome, not all cells within the body will use it, thus the production of FMRP is possible using the other normal X chromosome.