Where is the Fragile X gene located?
Fragile X syndrome is inherited in an X-linked dominant pattern . A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes.
Which locus loci is are associated with Fragile X syndrome *?
Phenotype-Gene Relationships
| Location | Phenotype | Gene/Locus |
|---|---|---|
| Xq27.3 | Fragile X syndrome | FMR1 |
Where is Fragile X syndrome most common?
Fragile X syndrome is the most common form of inherited intellectual disability in males and is also a significant cause of intellectual disability in females. It affects about 1 in 4,000 males and 1 in 8,000 females and occurs in all racial and ethnic groups.
Is Fragile X syndrome inherited from mother or father?
Fragile X is Inherited A mother who carries Fragile X has a 50% chance of passing the mutated gene to each of her children. Her children will either be carriers or they will have Fragile X syndrome.
What kind of mutation causes Fragile X syndrome?
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. In people with fragile X syndrome, however, the CGG segment is repeated more than 200 times.
Where is the FMR1 gene located in Fragile X syndrome?
On rare occasions some patients with fragile X syndrome are partially or completely missing the FMR1 gene due to a deletion of the DNA on the X chromosome where FMR1 is located and have the syndrome because their cells do not produce FMRP.
How many CGG repeats does fragile X syndrome have?
Individuals with fragile X syndrome nearly always have (in greater than 99% of cases) a full mutation of the FMR1 gene which means that they have over 200 CGG repeats and abnormal methylation of the gene.
Are there physical problems with Fragile X syndrome?
Physical problems that have been seen include eye, orthopedic, heart and skin problems. Girls who have the full FMR1 mutation have mild intellectual disability. Family members who have fewer repeats in the FMR1 gene may not have intellectual disability, but may have other problems.