Quack Myths: Fragile X Syndrome is the Same as Autism

*please excuse the ableism. These are not my terms, they are from the Fragile X society in the UK and the CDC.*

Fragile X syndrome  is the most common form of inherited intellectual disability in children. It is a genetic condition where there are changes in a gene that scientists call the fragile X mental retardation 1 (FMR1) gene when it was first discovered. Nearly all cases are caused by a 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 40 times. 

In people with fragile x syndrome, the CGG segment is repeated more than 200 times. FMR1 makes a protein called fragile x mental retardation protein (FMRP). FMRP is essential for typical brain development. 

People with fragile x syndrome do not produce this protein. People who have other conditions related to fragile x have changes in their FMR1 gene but usually have some production. 

Approximately 1 in 4000 AMAB have Fragile X syndrome and 1 in 8000 AFAB have Fragile X Syndrome. 


  • Developmental delays such as not sitting, walking or talking at the same time as other children at the same age
  • learning disabilities
  • social and behavior differences such as no eye contact, anxiety, trouble paying attention, hand flapping, acting and speaking impulsively, very active. 
AMAB children who have fragile x syndrome usually are intellectually disabled that can range from mild to severe. AFAB with fragile x syndrome have normal intelligence or some degree of intellectual disability. 

Testing and Diagnosis

Fragile x syndrome can be detected by testing the person’s DNA through a blood test. A doctor or genetic counselor can order the test if fragile x syndrome is suspected. Testing is also done to find changes in the FMR1 gene that can lead to related conditions. 
A diagnosis can help people working with the child understand the child and educate themselves about fragile x syndrome. 

Fragile X Syndrome is Not Autism

Fragile X Syndrome and autism are very similar. Fragile X syndrome there is a genetic test.  Autism is just a description of patterns and characteristics with a genetic component but there is no know cause. Many behaviors that Fragile X syndrome people have are autistic like. Only 1/3 of people with fragile x syndrome have enough of these characteristics meet the autism diagnostic criteria. Only 2-6% of autistic people have fragile X syndrome. 
Traits in people with Fragile X syndrome are more subtle than in autistic people. Autistic people with fragile X tend to be more socially responsive. 

2 thoughts on “Quack Myths: Fragile X Syndrome is the Same as Autism

  1. Pingback: Quackery Exposed:Psilocybin, substance in Magic Mushrooms – Fierce Autie

  2. Pingback: Bogus Study: Consumption of Breast Milk is Associated with Decreased Prevalence of Autism in Fragile X Syndrome – Fierce Autie

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