The following is a basic explanation of the family of Fragile X conditions. Please refer to your own countries Fragile X organization for more information and support.

What causes Fragile X?

The FMR1 gene produces a protein called FMR1-Protein (FMRP), which contributes to normal brain development and function.

On this gene there is a repeated sequence of chemical bases, known by the letters CGG. These are repeated a number of times.

Most people have less than 55 copies of this CGG repeat. Fragile X premutation carriers can have between 55 and 200 copies of the CGG repeat. People with the Fragile X full mutation (Fragile X syndrome) have over 200 copies of the CGG repeat.

Fragile X Syndrome

When the repeats on the Fragile X Gene (FMR1) increase beyond about 200, it switches off the production of a genetic protein causing the difficulties experienced in Fragile X Syndrome.

Symptoms may include intellectual disability, difficulties with learning, social language, attention, behavior and medical issues.  The number and severity of symtoms varies and females are usually less affected than males. Click the button below for a list of possible symptoms.

Fragile X Premutation Carriers

Premutation carriers of Fragile X have between 60-200 repeats on the Fragile X (FMR1) gene on their X chromosome.

Females have a 50% chance of passing this X onto their sons and daughters and the expansion on the FMR1 gene can increase. Their children will then either be premutation carriers themselves or have Fragile X Syndrome.

Premutation males will only pass their premutation status on to all of their daughters.

Premutation carriers may have medical, neurological and psychological problems which are distinct from those with Fragile X Syndrome although there are a minority that do experience Fragile X Syndrome symptoms. The suggested group name for these is FXVAC (Fragile X Premutation Associated Conditions)

FXVAC – Fragile X Premutation Associated Conditions

Carriers may experience one or more of these:

FXTAS

FXTAS is a neurological condition experienced mainly by some older male carriers. Fewer females have FXTAS and their symptoms tend to be less severe.

Symptoms can include intention tremor, balance problems, memory and decision making deficits and fibromyalgia

Awareness of Fragile X is important because those with FXTAS might be wrongly diagnosed with Parkinson’s Disease, Ataxia or Alzheimers.

Many more details about FXTAS can be found on the National Fragile X Foundation  site. 

FXPOI

FXPOI is a condition that occurs in about 20-25% of adult female premutation carriers because their ovaries do not function to their full capacity. There may not be sufficient eggs within the ovaries and these may be of lower quality for fertilization.

The condition can cause absent or irregular periods, problems with fertility and early menopause.

For more information and resources check out the FXPOI pages on the NFXF  and Fragile X Association Australia Sites or the main support organization in your own country.

FXAND

Recent research has shown that up to 50% of pre-mutation Fragile X carriers have some kind of of neuropsychiatric disorder.

In adults this is mainly anxiety disorders ( Generalized Anxiety Disorder, Specific Phobia, Social Phobia, sleep disorders), depression, problems with eye contact, and some with Obsessive-Compulsive behavior.

A higher percentage of female carriers suffer from these conditions.

Children may experience anxiety, ADHD, social deficits, or autism spectrum type symptoms. 

FXVAC

Although this term is used more in Europe it refers to other medical conditions which are more prevalent in the in pre-mutation carriers.

Pre-mutation carriers have a higher incidence of certain medical conditions such as:

• Fibromyalgia
• Migraines
• Neuropathy
• Autoimmune disorders
• Back problems
• High Blood Pressure
• Thyroid Disease

Some carriers do not have any symptoms at all.