"Fragile X Syndrome (also called FXS) is the most common cause of inherited mental retardation." (2011, University of Michigan Health System). "The gene on the X chromosome that causes FXS is called the Fragile X Mental Retardation 1 (FMR1) gene. The FMR1 gene makes a protein that is needed for normal brain development." (September 1, 2006. Department of Human Health and Services Center of Disease Control and Prevention.) When this protein is not made, that is when FXS occurs. Fragile X Syndrome is what is called a chromosomal sex-linked trait. A change or mutation in a gene on the X chromosome causes the Fragile X Syndrome. As human beings we have 46 chromosomes. In these 46 are two genes that are sex linked. These 2 chromosomes determine whether you are male or female. If you are male, your chromosomes are an X and a Y. If you are female you have two Xs. For example, when reproduction occurs each child receives a set of chromosome from each parent, there is a chance that out of four children, 2 will have this disorder. (Please refer to the chart below.)
Father with Muta0ted Gene MotheDr with Mutated Gene DOD0
0 =Male =Abnormal FMR1 Gen b =Female =Normal FMR1 Gene
Fragile X Syndrome is one of the genetic disorders that are grouped in what is called trinucleotide. "DNA is made up of four chemical building blocks called nucleotides: A, C,
T, and G." (September 1, 2006. Department of Human Health and Services Center of
Disease Control and Prevention.) When the trinucleotide repeat disorders repeat, they use 3 of these nucleotides. In everyone’s DNA it repeats, but it is only "dangerous" when they repeat many times, which causes the genes to not work correctly. "A normal FMR1 gene has between about 6 and 45 CGG repeats. People with FXS have over 200 CGG repeats." (September 1, 2006. Department of Human Health and Services Center of Disease Control and Prevention.) This disorder has many different forms, such as the type of mutation. When there is little change in the FMR1 gene it is called a permutation. When there is a significant change in the genes it is called a full mutation. Then these mutations are what actually cause the Fragile X Syndrome.
Fragile X has physical and mental signs that signify that a person may have this disorder. Some physical characteristics are "Prominent ears, large head, and prominent forehead, flexible finger joints, high palate, and flat feet. During puberty boys usually develop large testicles
(macroorchidism) and a long face." (2011. University of Michigan Health System). Some mental characteristics include: "Intelligence problems-ranging from mild learning disabilities to severe intellectual disability, cognitive development, Developmental delays-especially speech and language (most often in boys), Attention Deficit Hyperactivity Disorder (ADHD) or poor attention span, Autism and autistic behaviors-such as hand flapping, hand biting, chewing on
clothes, Social and emotional problems, such as aggression...