[Fragile X associated tremor/ataxia syndrome: its clinical presentation, pathology, and treatment]. / Sindrome de temblor y ataxia asociado al X fragil: presentacion clinica, patologia y tratamiento.

The fragile X associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disease associated with the repetition of CGG triplets (55-200 CGG repetitions) in the FMR1 gene. The premutation of the FMR1 gene, contrasting with the full mutation (more than 200 CGG repetitions), presents an increased production of messenger and a similar or slightly decreased production of FMRP protein. FXTAS affects 40% of men and 16% of women carriers of the premutation. It presents with a wide constellation of neurological signs such as intention tremor, cerebellar ataxia, parkinsonism, executive function deficits, peripheral neuropathy and cognitive decline leading to dementia among others. In this review, we present what is currently known about the molecular mechanism, the radiological findings and the pathology, as well as the complexity of the diagnosis and management of FXTAS.

TITLE: Sindrome de temblor y ataxia asociado al X fragil: presentacion clinica, patologia y tratamiento.El sindrome de temblor y ataxia asociado al X fragil (FXTAS) es una enfermedad neurodegenerativa relacionada con la premutacion del gen FMR1. Los alelos con premutacion (55-200 repeticiones de CGG), al contrario de los alelos con mutacion completa (mas de 200 repeticiones CGG), tienen una produccion excesiva de ARN mensajero y unos niveles normales o reducidos de proteina. El FXTAS afecta al 40% de los hombres y al 16% de las mujeres portadores de la premutacion de FMR1. Se presenta con una amplia variedad de signos neurologicos, como temblor de intencion, ataxia cerebelosa, parkinsonismo, deficit en la funcion ejecutiva, neuropatia periferica y deterioro cognitivo que conduce a la demencia, entre otros. En esta revision se presenta lo que hasta ahora se conoce del mecanismo molecular, los hallazgos radiologicos y la patologia, asi como tambien la complejidad del diagnostico y el tratamiento del FXTAS.

Compression injury in the mouse spinal cord elicits a specific proliferative response and distinct cell fate acquisition along rostro-caudal and dorso-ventral axes.

Harnessing the regenerative capabilities of endogenous precursor cells in the spinal cord may be a useful tool for clinical treatments aimed at replacing cells lost as a consequence of disease or trauma. To better understand the proliferative properties and differentiation potential of the adult spinal cord after injury, we used a mouse model of compression spinal cord injury (SCI). After injury, adult mice were administered BrdU to label mitotic cells and sacrificed at different time-points for immunohistochemical analysis. Our data show that the rate of proliferation increased in all regions of the spinal cord 1day after injury, peaked after 3days, and remained elevated for at least 14days after injury. Proliferation was greater at the injury epicenter than in rostral and caudal adjacent spinal segments. The number of proliferative cells and rate of proliferation varied between dorsal and ventral regions of the spinal cord and between the gray and white matter. Newly generated cells expressed markers for progenitor cells (Nestin and Olig2), oligodendrocytes (Sox10), astrocytes (S100b and glial fibrillary acidic protein), and microglia (Iba1), but not neuronal markers (Map2 and NeuN). Marker expression varied with regard to the dorso-ventral region, rostro-caudal proximity to the injury epicenter, and time after injury. At early time-points after injury, BrdU(+) cells mainly expressed microglial/macrophage and astrocytic markers, while at these same time-points in the control spinal cord the mitotic cells predominately expressed oligodendrocyte and oligodendrocyte progenitor cell markers. The profile of proliferation and cell fate marker expression indicates that after moderate compression, the spinal cord has the capacity to generate a variety of glial cells but not neurons, and that this pattern is space and time specific. Future studies should focus on ways to control proliferation and cell fate after injury to aid the development of cell replacement treatments for SCI.