María Isabel Quiroga de Michelena

A clinical study of 77 patients with mucopolysaccharidosis type II

Aim: This study aims to assess the clinical features of 77 South American patients (73 Brazilian) with mucopolysaccharidosis type II (MPS II).

CHMP1A encodes an essential regulator of BMI1-INK4A in cerebellar development

Charged multivesicular body protein 1A (CHMP1A; also known as chromatin-modifying protein 1A) is a member of the ESCRT-III (endosomal sorting complex required for transport-III) complex but is also suggested to localize to the nuclear matrix and regulate chromatin structure. Here, we show that loss-of-function mutations in human CHMP1A cause reduced cerebellar size (pontocerebellar hypoplasia) and reduced cerebral cortical size (microcephaly). CHMP1A-mutant cells show impaired proliferation, with increased expression of INK4A, a negative regulator of stem cell proliferation. Chromatin immunoprecipitation suggests loss of the normal INK4A repression by BMI in these cells. Morpholino-based knockdown of zebrafish chmp1a resulted in brain defects resembling those seen after bmi1a and bmi1b knockdown, which were partially rescued by INK4A ortholog knockdown, further supporting links between CHMP1A and BMI1-mediated regulation of INK4A. Our results suggest that CHMP1A serves as a critical link between cytoplasmic signals and BMI1-mediated chromatin modifications that regulate proliferation of central nervous system progenitor cells.

Genética y preeclampsia

Preeclampsia is a multifactorial and complex condition whose etiology continues in study. Identification of genes involved in preeclampsia may lead to markers that may predict and/or detect preeclampsia, and the discovery of specific and personalized treatments. Keywords: Preeclampsia, genetics.

Enfermedad de Tay-Sachs

La enfermedad de Tay-Sachs es la forma mas comun de neurolipidosis hereditaria, transtorno familiar que se presenta en judios del este de Europa en una proporcion de 1 en 360 casos y en no judios en 1 en 6000 nacidos vivos. Se debe a una deficiencia de la isoenzima BN –acetil hexosaminidasa, que produce una acumulacion de gangliosido GM 2 intraneuronal (1).

Sindrome de Rett: descripción de dos casos

El Sindrome de Rett (SR) fue descrito inicialmente en 1966 por Andreas Rett. Comprende una involucion mental progresiva de inicio antes de los dos anos acompanada de perdida de contacto social y movimientos estereotipados de las manos, apraxia /ataxia de la marcha y crisis de hiperventilacion, presentandose exclusivamente en mujeres (1).