Recent research shows that carriers – 1 in 260 women and 1 in 800 men – can also have symptoms. Some older men who are carriers (and rarely women) will be impaired by Fragile X-associated Tremor Ataxia Syndrome (FXTAS).
Carriers are generally thought to be spared most of the problems associated with the full mutation. However, a newly identified neurological disorder appears to specifically affect some older premutation carriers, generally grandfathers of children with Fragile X syndrome.
Although FXTAS occurs by a completely separate mechanism from Fragile X syndrome, it is caused by the same gene, and therefore opens a new portal for understanding how the Fragile X gene works.
- Progressively more severe intention tremor – shaking that often occurs when reaching for or pouring something
- Balance problems (ataxia) that cause falling or instability while walking
- Numbness in the extremities (neuropathy)
- Mood instability, irritability, and other changes in personality
- Short-term memory loss and gradual intellectual decline
The diagnosis is based on 3 factors:
FXTAS usually develops between the ages of 50-80 and symptoms that family members may notice are often attribute to aging. Individuals with FXTAS may be misdiagnosed with other conditions including Parkinson's disease, Alzheimer's disease, dementia, stroke, and peripheral neuropathy.
- Positive carrier testing for the FMR1 premutation,
- A neurological exam that affirms the above characteristics, and
- Magnetic Resonance Imaging (MRI) findings that are known to be related to FXTAS.
Anyone experiencing any of the symptoms described above should contact their physician and request a referral to a neurologist.
FXTAS can be misdiagnosed
Because the symptoms of FXTAS mimic symptoms of other higher profile conditions, such as Parkinson's disease – it can often be misdiagnosed.