Genetics Disorder Fragile X

By: Tyler Weaks


The disease I chose is known as Fragile X. Basically Fragile X is a disorder that has to do with your brain and it impairs your learning ability and cause mental retardation. It is inherited genetically and affects mostly males.

The Disease

This disease mostly affects the brain. It causes mental retardation. This disease is a genetic disease that causes a lot of problems in the development of someone’s learning. This disease can cause learning disabilities and cognitive impairment. Most of the time males are more likely to get this disease than females. You can usually tell if small children are affected by age 2 is when the disease starts to show delayed development of speech and language. Most males have moderate to mild intellectual disabilities. About only 1/3 of affected females have intellectual disabilities. Young children that have this disease usually also have anxiety and hyperactivity, which can be seen by fidgeting and impulsive actions. They may also have ADD (Attention Deficit Disorder). Which if they have that it may cause them to not be able to sit still or focus on certain topics. About 1/3 of all affected have signs of autism. Those signs include communication hinderance and social interaction hinderance. Seizures occur in about 15% of males and then only 5% of females.


Everyone that is diagnosed with Fragile X doesn't have the same signs and symptoms, or to the same degree. Affected children in the same family can even have different symptoms. These differences often make Fragile X hard to diagnose. However, because everyone with Fragile X has too little FMRP, they do share a pattern of certain physical, social, mental, and sensory characteristics.

In general, the signs and symptoms of Fragile X fall into five categories:

  • Intelligence and learning
  • Physical
  • Social and emotional
  • Speech and language
  • Sensory
  • Disorders commonly associated or sharing features with Fragile X

Most people with Fragile X have impaired intellectual functioning, which affects their ability to think, reason, and learn.

Cause of the Disorder

The cause of the disorder is when a X-link in a chromosome is mutated in the FMR1 gene where a DNA segment is repeated exponentially too many times. This repetition of the segment causes the muting of the FMR1 gene which creates a mental retardation protein. And when that protein is not present then it will cause mental retardation and learning problems.

How the Disorder is inherited

It is inherited in a dominant X-linked pattern. The disease is considered X-linked if the mutation occurred in the X chromosome. The inheritance is dominant if one copy of the altered gene in each cell is sufficient to cause the condition. Most of the time males experience more severe symptoms than females. A big characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. So in other words it is passed down through the mother.

How the disorder is treated

There is no specified treatment yet for the Fragile X syndrome. The only thing that they can do is special education, medication to manage behavior, and early intervention with special education.

How the disease is diagnosed

In most cases, scientists use an intelligence test to measure intellectual functioning, resulting in an IQ (intelligence quotient) score. This score also reflects many things besides the ability to think. Attention disorders, hyperactivity, anxiety, and language processing problems can interfere with test-taking skills and learning.

Researchers consider people who score between 85 and 115 on an IQ test to have "average" intelligence. On the whole, less than 20% of males with Fragile X have an IQ in this range. At the same time, few people with Fragile X are severely or profoundly impaired, with IQs below 40 or 25, respectively. In general, those with a full mutation tend to have an IQ somewhere in between 40 and 85, which is considered mild to moderate mental impairment.

How many and what type of people are most likely to get this disease

This disease is pretty rare because it only occurs in about every 1 in 4,000 males and only 1 in 8,000 females. It more severely affects males, but will also cause mental retardation in females as well.

Application of Research

I have learned how this disease can effect people and how serious it can be for this to take place inside of a person. I one day hope that scientists will be able to find a cure for this disease. Knowing more now about this and the symptoms/signs I can probably know more about what could be the problem with some of the people in our school who have this disease.

Works Cited

Works Cited

Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 27 Aug. 2013. Web. 21 May 2014.

"Fragile X Syndrome." - Genetics Home Reference. Web. 20 May 2014.

"Fragile X Syndrome (Fragile X-associated Disorders)." National Fragile X Foundation RSS. Web. 20 May 2014.

"Fragile X Syndrome Symptoms, Causes, Treatment - What Are the Signs and Symptoms of Fragile X Syndrome? - MedicineNet." MedicineNet. Web. 22 May 2014.

"Learning About Fragile X Syndrome." Learning About Fragile X Syndrome. Web. 22 May 2014.