Etiology:
Etiology Fragile X is caused by a defect in a gene called FMR-1, which is located on the X chromosome FMR-1 contains DNA of a segment CGG On a normal FMR-1 gene CGG triplet repeat is repeated 5 to 40 times On a person with Fragile X syndrome this CGG segment is repeated 40 to 200 times The more repetitions of CGG triplet repeat the more severe the symptoms are. CGG shuts down the FMR-1 and stops the production of a protein called FMRP.
Characteristics:
Characteristics Mild to Moderate intellectual disabilities Motor and Language delays Behavior abnormalities similar to Autism Physical features: Large head, long face, prominent forehead and chin, protruding ears, loose joints
Prevalence:
Prevalence More often in males than females Males= 1 in every 4,000 Females= 1 in every 8,000
Diagnosis:
Diagnosis Southern Bolt Analysis Determines if the gene has full mutation and its approximate size Polymerase Chain Reaction (PCR) Determines the actual number of CGG repeats
Resources For Families:
Resources For Families www.FragileX.org www.raredisease.org www.aafp.org www.fraxa.org www.ghr.nlm.nih.gov