Our bodies are made up of millions of cells. Each cell contains thousands of genes. Genes are like a set of instructions, controlling our growth and how our bodies work. Genes are responsible for many of our characteristics such as our eye colour, blood type or height. Any alteration in a gene can stop a gene working properly.
Genes are carried on thread like structures called chromosomes. Chromosomes are arranged in 23 pairs, according to size. We normally inherit one of each of the pairs from our mother and one from our father. Twenty two of these are the same in both sexes. The twenty third pair are the sex chromosomes. Women have two X chromosomes (XX) and men have an X and a Y chromosome (XY).
The gene that causes FXS lies near the tip of the X chromosome. Under a microscope, the tip looks like it has broken off but not quite separated. This is how the disorder got its name.
At the beginning of the normal fragile X gene a small part of the genetic code is repeated several times. In people with FXS the repeated part of the gene is larger than normal (they have more repeats). This is called an expansion, because part of the gene has grown bigger or expanded. If it grows too big it interferes with the normal instructions and causes fragile X.
Experimental drug to treat fragile X syndrome
The drug is still in an early stage of development, but its success gives researchers courage to move on to larger trials that may lead to a filing for approval with the Food and Drug Administration.
The drug holds promise for the future treatment of fragile X syndrome, the most common form of inherited intellectual disability in boys, said Robert T. Schultz, Director of the Center for Autism Research at the Children's Hospital of Philadelphia.
Fox News
Retired teacher active with Fragile X Foundation
Age: 61
Residence: Highland Beach
Family: Husband, Michael; two sons
Career: Retired teacher
Cause: The National Fragile X Foundation, an organization formed in 1984 to help families, spread awareness and support research for all Fragile X-associated disorders.
Q: Why do you volunteer?
A: I was the mother of a son who had something wrong with him, but no one could say what. Before Dan became diagnosed with Fragile X at 21, I had to go it alone without much help. I volunteer so other people don't go through what I did.
A: NAXF is the largest and strongest group lobbying to support research in Fragile X. They also offer support and information to people concerning Fragile X-associated disorders. It's where I can make the greatest difference in helping others.
Q: Describe your volunteer role.
A: I am a volunteer at Dan's weekly bowling league in Boca Raton. For the Special Olympics, I volunteer at the adult bowling group. Through NAXF, once a year I go toWashington, D.C., to lobby for continued federal research funding. On July 25-29, the Fragile X conference will be in Miami, and I am co-chair for recruiting volunteers. And I advocate for all special-needs adults.
Q: What are your goals?
A: My short-term goal is to recruit 50 volunteers for the NAFX convention. My ongoing goal is to spread the word about Fragile X syndrome so that more of the population gets tested. When Dan was born 34 years ago, no accurate blood tests existed; today they do. This means families should be tested. My grandmother, mother, aunt and I were all silent carriers.
Q: What challenges do you face?
A: Dan doesn't have the ability to live on his own yet. He is very good in a routine, but not in handling change or in always reacting appropriately. Right now, he still needs an advocate in his corner. But he continues to grow and his abilities continue to increase, so I'm optimistic.
Q: What has Dan accomplished?
A: Since he was 17, Dan has worked at McDonald's, first in Chicago and now in Boca. He tried several jobs initially, but he loved McDonald's. Actually, he's so well trained he can work at any McDonald's in the world. The supervisor in Boca said, "I thought I'd give him a chance, but I never expected him to be so good."
Q: What have you personally accomplished?
A: I've just reissued as an eBook "The Broken Toy: A Story of a Fragile X Syndrome Child." It's to help parents of special-needs children, starting from childhood and going into adulthood. [Visit] http://www.brokentoybook.com.
Q: What does your organization need?
A: Increased awareness of Fragile X and the progress being made to find a cure.
For more information, please visit http://www.fragilex.org.
Frequently Asked Questions
Did I do anything to cause fragile X syndrome?No. There is nothing you did before or during the pregnancy or after your child was born to cause fragile X syndrome. Fragile X syndrome is genetic which means it is caused by a change in a gene, in this case, the FMR1 gene. The change causes the gene not to work the way it should, leading to the problems seen in fragile X syndrome.
Because fragile X syndrome is genetic, it can be passed on and you are at risk for having another child with fragile X syndrome. It is important to know that you have no control over whether this change gets passed on to your child or not. In addition, other family members may also be at risk of having children with fragile X syndrome, so it is important to inform them of your child's diagnosis.
What does cause fragile X syndrome?
Explaining how fragile X happens is not very easy simply because of the way it is inherited. To start, let's talk broadly about genes and chromosomes. Genes are the instructions that tell our bodies how to work and are made up of DNA. We inherit two copies of all of our genes: one copy from our mother and one copy from our father. The DNA is packed into larger structures called chromosomes, and each chromosome contains hundreds to thousands of genes. Most people have 23 pairs of chromosomes, for a total of 46 chromosomes. The first 22 pairs are the same in males and females and are called the autosomes. The 23rd pair, called the sex chromosomes, are different in males and females. Females have two "X" chromosomes, and males have one "X" and one "Y" chromosome.
Fragile X is caused by a change in the FMR1 gene on the X chromosome that causes it not to work properly. Everyone has 6-10 genes that don't work the way they should, but this generally does not cause a problem. However, the change in the FMR1 gene does make a difference. This change (also called a mutation) in the FMR1 gene is complex and occurs over many generations.
The FMR1 gene contains a section of repetitive DNA that in most of the population is only 10-40 repeats long. In those with fragile X syndrome, this repeated region has expanded to over 200 repeats. When a repeat length is greater than 200, it is referred to as a full mutation or expansion. At this size, the FMR1 gene cannot function and the FMR1 protein cannot be produced. It is the inability of cells to make this protein that is responsible for fragile X syndrome.
In general, every person gets two copies of every gene. This is a little bit different for the FMR1 gene because it is on the "X" chromosome. Because males have only one "X" chromosome, they have only one copy of the FMR1 gene. If they have a full mutation, their one copy of the FMR1 gene is not working, and one sees the signs of fragile X syndrome. Because females have two "X" chromosomes and 2 copies of the FMR1 gene, if a girl inherits a full mutation, the other copy of the gene is usually working, so girls with a full mutation are still able to make FMR1 protein. This is why girls usually have fewer signs of fragile X than boys do.
In general, we expect to see the full mutation in every cell of a person with fragile X syndrome. Sometimes, however, an individual with fragile X syndrome can have what is called mosaicism. There are two kinds of mosaicism in fragile X syndrome: repeat size mosaicism and methylation mosaicism. In repeat size mosaicism, an individual has some cells that have a full mutation and some cells that have a premutation. In methylation mosaicism, all the cells have a full mutation, but the methylation pattern may not be the same in all cells. Some research studies have shown that individuals with repeat size or methylation mosaicism may be less affected than those who do not have mosaicism.
What is methylation?
Methylation is a process in which a chemical group, called a methyl group, gets added to the DNA. When enough methyl groups are added to the DNA, the gene gets turned off. When methyl groups are removed, the gene gets turned on. This is a normal process and many of our genes are controlled by methylation. However, in fragile X syndrome, the methylation of the FMR1 gene turns the gene off when it should be turned on. When FMR1 is turned off, its protein is not made, and you see the features of fragile X syndrome.
When someone with fragile X syndrome has methylation mosaicism, not all cells will have the FMR1 gene turned off by methylation. Some cells may have it partially turned off, and some cells may have the FMR1 gene turned on.
I heard only boys have fragile X syndrome. Why does my daughter have it also?
Girls can also have fragile X syndrome even though they have two "X" chromosomes. The reason is that they have a full expansion on one chromosome and a normal repeat section (in most cases) on the other chromosome. The copy with the full expansion is not making any FMR1 protein, while the other copy (the normal repeat section) is making protein. Although some protein is being made, it may not be enough, so we can see characteristics of fragile X syndrome. However, because some protein is being made, girls with fragile X syndrome are generally less affected than boys.
Is there a cure?
At this time, there is no cure for fragile X syndrome. Treatment for fragile X syndrome is provided through therapies such as special education, speech and language therapy, and occupational therapy. Medications may be helpful in managing hyperactivity, short attention span, and other behavioral or emotional problems. In order to determine the best course of action for your child, a comprehensive evaluation is recommended.
Source: www.childrenshospital.org
Fragile X Syndrome Facebook
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Fragile X Syndrome & Autism
Fragile X Syndrome & Autism
what is pre-mutation ?
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