Understanding Fragile X Terminology

Posted bycdcjdc1617Posted inautism, Fragile X, Special NeedsTags:, , , , ,

Hi All! Today, I wanted to take sometime and talk through some of the different terms you hear when you talk about Fragile X Syndrome. When you get a diagnosis of Fragile X Syndrome, you are hit with a lot of emotions like uncertainty, helplessness, guilt, anger, sadness, confusion and the list goes on and on. Then, you do what most people do and run to the internet to try and make sense of it all. You find information that is overwhelming, unclear, doom and gloom and you struggle to know what the future looks like for your child and your family. To make things even harder to process there are more types of Fragile X such as full mutation with partial methylation, mosaicism, Fragile X with a dual diagnosis of Autism. I will tell you from first-hand experience, when we received Jackson’s diagnosis, the doctor called me and confirmed he had Fragile X. She then stated it said partial methylation on the report, but she didn’t know what that meant. Imagine how we were feeling that she had no clue the results she was sharing with us. After we went to the Cincinnati Children’s Hospital and participated in some research studies and some tests were performed we learned Jackson was mosaic (see below what that means). So, let’s look at a few of the main terms you might hear.

  • Fragile X Syndrome – Fragile X syndrome (FXS) is the most common inherited cause of autism and intellectual disabilities worldwide. To have a diagnosis of Fragile X Syndrome would mean you have 200 or more repeats of your CGG in your FMR1 gene, which shuts off the gene, meaning no protein is being developed. That protein is what is needed for brain development.

While it seems straightforward that if you have 200 or more repeats you have a diagnosis and that is where you are left, however, there is also something called Mosaicism, which Jackson has.

  • Mosaicism – Among those who have the fragile X mutation, there are a group termed “mosaic”. There are two kinds of mosaicism in Fragile X Syndrome: repeat size mosaicism and methylation mosaicism. In repeat size, an individual has some cells that have a full mutation and some cells that have a premutation. In methylation mosaicism, all cells have a full mutation, but the methylation pattern may not be the same in all cells. Some studies have shown that individuals with either mosaicism may be less affected that those who do not have mosaicism.
  • Methylation – Methylation is a process in which a chemical group, called a methyl group, gets added to the DNA. When enough methyl groups are added to the DNA, the gene gets turned off. When methyl groups are removed, the gene gets turned on. This is a normal process and many of our genes are controlled by methylation. However, in fragile X syndrome, the methylation of the FMR1 gene turns the gene off when it should be turned on. When FMR1 is turned off, its protein is not made, and you see the features of fragile X syndrome.
  • Autism – Autism is a complex, lifelong developmental disability that typically appears during early childhood and can impact a person’s social skills, communication, relationships, and self-regulation. Autism is defined by a certain set of behaviors and is a “spectrum condition” that affects people differently and to varying degrees.

Like other syndromes, diseases and diagnoses Fragile X is not just a cookie cutter diagnosis. I hope this information was helpful. Keep spreading awareness, acceptance and love!

XOXO

Sources:

Leave a comment