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The recent identification of fragile X-associated tremor ataxia syndrome (FXTAS) associated with premutations in the FMR1 gene and the possibility of clinical overlap with multiple system atrophy (MSA) has raised important questions, such as whether genetic testing for FXTAS should be performed routinely in MSA and whether positive cases might affect the specificity of current MSA diagnostic criteria. We genotyped 507 patients with clinically diagnosed or pathologically proven MSA for FMR1 repeat length. Among the 426 clinically diagnosed cases, we identified four patients carrying FMR1 premutations (0.94%). Within the subgroup of patients with probable MSA-C, three of 76 patients (3.95%) carried premutations. We identified no premutation carriers among 81 patients with pathologically proven MSA and only one carrier among 622 controls (0.16%). Our results suggest that, with proper application of current diagnostic criteria, FXTAS is very unlikely to be confused with MSA. However, slowly progressive disease or predominant tremor are useful red flags and should prompt the consideration of FXTAS. On the basis of our data, the EMSA Study Group does not recommend routine FMR1 genotyping in typical MSA patients.

Paroxysmal kinesigenic choreoathetosis (PKC) is a neurological condition which results in abnormal involuntary movements that are precipitated by sudden movement. Because of its rarity, large case series of PKC have not been published. We studied 26 patients with PKC, which represents the largest series thus reported. We reviewed our cases with respect to attack characteristics, aetiology, family history, and treatment response. Our population consisted of 23 men and 3 women. Seven patients had a family history of paroxysmal dyskinesia. None of our patients had clear evidence of symptomatic PKC. Two-thirds of our patients had attacks lasting between 30-60 s, and over one-half experienced one to ten attacks per day. Attack distribution varied widely, and most experienced pure dystonia rather than choreodystonic movements. Most patients responded very well to anticonvulsant therapy. We also report the PET results from two of our patients and Bereitschaftspotential abnormalities recorded from two others.

The clinical features and natural history of 18 patients with adult onset axial predominant severe truncal primary dystonia are presented. The mean age of onset was 41 (42 for men, 39 for women) and there was a higher proportion of men (10:8). Analysis of their clinical features and follow up over three to five years or more showed that these patients generally conform to the characteristics of other types of adult onset primary dystonias. They tended to remain focal although there could be an initial contiguous spread, sometimes beginning in the craniocervical region and spreading axially or, rarely, vice versa. If spread occurred, involvement of the head, neck, and arms was mild in comparison with the severe dystonia of the trunk. However, in none of the patients with craniocervical or truncal onset did the dystonia spread to involve the legs. More than a third (seven of 18) of the patients had a prior history of injury at the site subsequently aVected by dystonia. Treatment response to various drugs overall was poor but a third of the patients improved on treatment either with triple therapy (a combination of tetrabenazine, pimozide, and an anticholinergic drug) or high dose anticholinergic drugs alone. Severe depression occurred in 33% of patients, mainly due to the negative personal image arising from their disfiguring dystonia. None of the patients had a family history of dystonia and at the moment it is unclear whether these patients with sporadic axial dystonia are non-genetic phenocopies or are a manifestation of one or more of the genes that cause generalised dystonia or torticollis.

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