Over the last year or so I've written some short pieces about Fragile X Syndrome, but I've never written a primer about it. It is timely to do so now for a couple of reasons. First, a group of Fragile X advocates - parents, doctors, therapists and researchers - recently completed an annual trip to Washington, D.C. to meet with various congressional leaders to encourage them to increase funding for research into Fragile X Syndrome, and to sponsor legislation to benefit individuals with Fragile X and other special needs. Second, in just a few short days Autism Awareness Month (April) will begin.
Are you aware that for 2-6% of all individuals diagnosed with autism, the Fragile X gene mutation is the cause? That may not sound like much, but it is the largest known, single-gene mutation cause of autism. You can learn more about the distinction between the two disorders and the link between them by reading here. Suffice it to say that anyone diagnosed with autism should be tested for the Fragile X mutation and that any strides toward understanding and treating Fragile X may help us learn more about autism, too.
Fragile X is also the most common inherited form of cognitive disability. It begins as a mutation on a gene (FMR1) found on the X chromosome. This mutation affects the structure of the X-chromosome such that under magnification it actually looks "broken", hence the name of the disorder. The FMR1 gene is responsible for instructing cells how to make the protein FMRP. The role of FMRP is not known, but clearly has some role in brain development. In the simplest scenario, because FMR1 is located on the X-chromosome, Fragile-X is carried by females. Since females have two X-chromosomes one can still generate FMRP if the other bears the FMR1 mutation; they have the mutation, but not the disorder. Males with a fragile X cannot make FMRP and will develop the characteristics of Fragile X Syndrome. However, both males and females can be carriers and both males and females can have Fragile X, so it's complicated.
In addition to behavioral characteristics that are similar to autism (language delays, motor delays, sensory disorder, poor eye contact, etc.) often individuals with Fragile X have some physical characteristics in common (large ears, long face, soft skin, flexible joints, and flat feet). Usually there are cognitive issues ranging from mild learning differences to severe cognitive disabilities.
To learn more about Fragile X, I recommend starting at the National Fragile X Foundation website. In particular, this video, which I have linked to before is very powerful.