Fragile X tremor ataxia syndrome (FXTAS)

FXTAS is due to premutation, and an excess amount of FRMP protein (50-200 repeats). Not all carriers develop FXTAS. Features include

1. usually presents with intention or action tremor with handwriting or using utensils

2. above is followed by ataxia with falls and unstable gait
above occurs in male carriers at a rate of 17% by 50's, 38 % by 60's, 47 % by 70's and 75 % by 80's. Women have less FXTAS with 8 % of those with premutation affected.

Other neurologic features
1. painful neuropathy

2. autonomic dusfunction (erectile dysfunction, hypertension, OH, urinary urgency and frequency, and incontinence.  Girls develop premature ovarian insufficiency or POI. 

3. White matter abnormalities (increased T2 intensity)especially bilateral cerebellar peduncles but elsewhere in deep white matter(seen in 60 % males, 13 % of females)

4. Executive dysfunction, short term memory loss, disinhibition and dementia

5. Unique eosinophilic intranuclear inclusions in neurons and astrocytes especially in the hippocampus and in the limbic system that are tau negative. They also occur in the PNS including the pericardiac and mesenteric ganglia and Leydig cells of testes.

6. Testosterone deficiency

7. Anxiety, social phobia and depression

8. Women with FXTAS : 43 % have fibromyalgia and 50 % have thyroid disease usually hypothyroidism

9. 2-3 per 100 develop multiple sclerosis and some develop Alzheimers

Treatment: SSRI's for anxiety, lithium for depression