ABSTRACT
Neuronal intranuclear inclusion disease (NIID) is a slowly progressive neurodegenerative disease characterized by localized neuronal loss,and the presence of eosinophilic intranuclear inclusions in neurons and glial cells.Biopsy samples of skin,rectal and sural nerve showed hyaline intranuclear inclusions.Reported NIID cases showed familial type according to family history,and three clinical subgroups (infantile,juvenile and adult form) according to onset and disease duration.NIID has been considered as a heterogeneous disease because of the highly variable clinical manifestations including cognitive dysfunction,parkinsonism,cerebellar ataxia,peripheral neuropathy and autonomic dysfunction.Additionally,some NIID cases presented episodes of conscious disturbance,cognitive decline,movement disorder or even fever.Head magnetic resonance imaging of some patients revealed symmetrical leukoencephalopathy in T2 image and fluid attenuated inversion recovery image and high intensity signal in corticomedullary junction in diffusion weighted image.But it is not the only abnormal finding of imaging,and other diseases may also present the similar changing.Other diseases including fragile X-associated tremor-ataxia syndrome,Huntington's disease and spinocerebellar ataxia should be considered in differential diagnosis.
ABSTRACT
FXTAS (Fragile X-associated tremor and ataxia syndrome) is a late- onset neurodegenerative disorder affecting mainly men, over 50 years of age, who are carriers of the FMR1 gene premutation. The full mutation of this gene causes the fragile X syndrome (FXS), the most common cause of inherited mental retardation. Individuals affected by FXTAS generally present intention tremor and gait ataxia that might be associated to specific radiological and/or neuropathological signs. Other features commonly observed are parkinsonism, cognitive decline, peripheral neuropathy and autonomic dysfunction. Nearly a decade after its clinical characterization, FXTAS is poorly recognized in Brazil. Here we present a review of the current knowledge on the clinical, genetic and diagnostic aspects of the disease.
A FXTAS (síndrome de tremor e ataxia associada ao X frágil) é uma doença neurodegenerativa de início tardio que afeta principalmente homens acima dos 50 anos de idade, portadores de pré-mutação do gene FMR1. A mutação completa desse gene é responsável pela síndrome do cromossomo X frágil (SXF), a causa mais comum de deficiência mental herdada. Indivíduos afetados pela FXTAS geralmente apresentam tremor de intenção e ataxia de marcha que podem estar associados a sinais radiológicos ou neuropatológicos específicos. Outras características comumente observadas são parkinsonismo, declínio cognitivo, neuropatia periférica e disfunções autonômicas. Quase uma década após sua caracterização clínica, a FXTAS é mal conhecida por médicos no Brasil. Esta revisão apresenta o conhecimento atual sobre os aspectos clínicos, genéticos e diagnósticos da síndrome.