What does Fragile X Syndrome look like?

These features include a long and narrow face , large ears, a prominent jaw and forehead, unusually flexible fingers, flat feet , and in males, enlarged testicles (macroorchidism) after puberty.

What is Fragile X syndrome FMR1?

Fragile X syndrome occurs in individuals with an FMR1 full mutation or other loss-of-function variant and is nearly always characterized in affected males by developmental delay and intellectual disability along with a variety of behavioral issues. Autism spectrum disorder is present in 50%-70% of individuals with FXS.

Why do females have milder symptoms of fragile X syndrome than males?

Symptoms of Fragile-X syndrome are more severe in males compared with females. Because females have two X chromosomes, an inherited damaged FMR1 gene can be compensated for by an inherited healthy FMR1 gene. Unlike females, males only have one X chromosome, so an inherited damaged copy is their only copy.

How is a change in the FMR1 gene related to Fragile X?

Fragile X syndrome and its associated conditions are caused by changes (mutations) in the FMR1 gene found on the X chromosome. This mutation affects how the body makes the Fragile X Mental Retardation Protein, or FMRP. The mutation causes the body to make only a little bit or none of the protein, which can cause the symptoms of Fragile X.

How is fragile X mental retardation ( FXS ) syndrome inherited?

FXS is caused by a change in the fragile X mental retardation 1 (FMR1) gene. The FMR1 gene makes a protein called fragile X mental retardation protein (FMRP) that is needed for normal brain development. Genes are found on chromosomes. Every human cell contains 23 pairs of chromosomes. People get their chromosomes from their parents.

Can a man with Fragile X syndrome have a daughter?

Anyone with the FMR1 gene mutation can pass it to their children. However, a person who inherits the gene mutation may not develop Fragile X syndrome. Males will pass it down to all of their daughters and not their sons. Females have a 50/50 chance to pass it along to both their sons and daughters.

What causes the CGG triplet repeat in Fragile X?

Nearly all cases of fragile X syndrome are caused by an alteration (mutation) in the FMR1 gene where a DNA segment, known as the CGG triplet repeat, is expanded. Normally, this DNA segment is repeated from 5 to about 40 times.