[Fragile X premutation presenting as postural tremor and ataxia (FXTAS syndrome)]. / Tremblement postural et ataxie révélant une prémutation X fragile ou syndrome FXTAS.

We report a case of FXTAS in a 58-year-old man who presented with postural tremor, mild ataxia and dysexecutive cognitive signs. The syndrome had a slow progressive course. Brain imaging by MRI showed characteristic abnormalities with mild cerebellar atrophy, symmetric high signals in the middle cerebellar peduncles and in the subcortical white matter of cerebral hemispheres. The diagnosis was confirmed by molecular genetics showing by southern blot a 100-120 expansion repeat of the CGG trinucleotide. FXTAS is a recently described syndrome, still unknown by most neurologists and probably rather frequent in men older than 60. We emphasize the value of clinical evaluation and brain imaging by MRI in some patients presenting with non specific motor or cognitive symptoms. A diagnosis of FXTAS may have implications for genetic counselling of female relatives.

Case report of pallido-pyramidal disease with supplementary motor area involvement.

An C-flumazenil positron emission tomography (PET) study in a patient with pallido-pyramidal disease revealed a marked decrease in benzodiazepine-receptor density in the precentral gyrus cortex and the mesial frontal cortex. We suggest that, in addition to dysfunction of basal ganglia-dependent systems, degeneration of the supplementary motor area could also be involved in the patient's bradykinesia.

[Diagnostic criteria of borderline forms of multiple sclerosis]. / Critères diagnostiques des formes frontières de sclérose en plaques.

Border forms of multiple sclerosis (MS) can be separated in two groups: either they are variants of MS or they are distinct from MS but they share several characteristics with MS thus representing for some of them a continuum with MS. All these entities are central nervous system demyelinating diseases. Here we describe, for the first group, MS in childhood, MS in elderly subjects, Balò's concentric sclerosis, Schilder's myelinoclastic diffuse sclerosis and MS simulating a mass lesion, and for the second group, acute disseminated encephalomyelitis and Devic's neuromyelitis optica.

[Diagnostic criteria of multiple sclerosis in neuroimaging]. / Critères diagnostiques de la sclérose en plaques en neuroimagerie.

To date, there is no biological test available with enough confidence to make alone a diagnosis of Multiple Sclerosis (MS). MS diagnosis criteria are then an association of clinical and para clinical criteria that allow an objective demonstration of dissemination of lesions in both time and space. Adapted MRI criteria from Barkhof have a good sensitivity and the best specificity to evaluate MS. 3 of 4 criteria are necessary: 1 gadolinium enhancing lesion or 9 T2 hyper intense lesions; at least 1 infratentorial lesion; at least 1 juxtacortical lesion; at least four periventricular lesions; NB: 1 spinal cord lesion can substitute for 1 brain lesion. News methods as spectroscopy, magnetization transfer, diffusion MRI and functional MRI complete results of conventional MRI and give new informations about physiopathology of MS demyelinating lesions.