When I have to explain it to someone I usually say that Fragile x is like Autism but it’s genetic.
It occurs when part of the DNA string in the SMR1 gene in the X chromosome expands and shuts down, failing to produce a protein for normal brain development.
Okay, now let’s take that slower.
We’ve all seen pictures of DNA strands. The part that deals with Fragile X is called the CGG segment. People without FX have this DNA segment repeated from 5 to about 40 times. That’s average. I am a carrier. So males and females with 55 to 200 repeats of the CGG segment are said to be premutation carriers. I have 72 repeats. A full mutation is defined as over 200 CGG repeats, and that is what my son has. BUT my son is also mosaic, which is even more confusing. In Fragile X, this means that some cells may have 200 or more repeats, while other cells, premutation cells, may have fewer than 200 repeats. Basically he makes some of the protein his brain needs but still not the proper amount.
Some Symptoms of Fragile X
- Trouble learning skills like sitting, crawling, or walking
- Problems with language and speech
- Hand-flapping and not making eye contact
- Temper tantrums
- Poor impulse control
- Extreme sensitivity to light or sound
- Hyperactivity and trouble paying attention
- Aggressive and self-destructive behavior in boys