Artículo
May anomalous X chromosome methylation be responsible for the spontaneous abortion of a male foetus?
Autor/es | Martinez, R.
Bonilla Henao, Victoria Ramos, I. Sobrino, Francisco Lucas, Miguel Pintado Sanjuán, Elizabeth |
Departamento | Universidad de Sevilla. Departamento de Fisiología Médica y Biofísica Universidad de Sevilla. Departamento de Bioquímica Médica y Biología Molecular e Inmunología |
Fecha de publicación | 2008-12-01 |
Fecha de depósito | 2017-06-09 |
Publicado en |
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Resumen | Pregnancy loss is an important reproductive problem which appears to be highly associated with genetic factors. A spontaneous abortion occurred before prenatal diagnosis could be performed, in a woman who carried a fragile ... Pregnancy loss is an important reproductive problem which appears to be highly associated with genetic factors. A spontaneous abortion occurred before prenatal diagnosis could be performed, in a woman who carried a fragile X full mutation. DNA extracted from formalin-fixed para ffin-embedded chorionic villi preparations indicated that it was a male embryo with an apparently methylated X chromosome. The previous analysis of the family showed that her daughter, who also carried a full mutation, exhibited an extremely skewed X inactivation of the normal allele (100%) and a severe fragile X phenotype. Thus, we speculate that the aberrant pattern of X chromosome methylation in this family may provoke the spontaneous miscarriage of this pregnancy that could be explained by at least partial inactivation of the unique X chromosome in a male foetus. Spontaneous abortion occurs quite frequently in humans, and recurrent pregnancy loss is a significant problem in women’s health (Christiansen 2006). Many cases of spontaneous abortion defy diagnosis and genetic factors have been proposed as a major contribution (Lanasa and Hogge 2000; Sierra and Stephenson 2006). The X chromosome inactiva tion (XCI) is the process in which one of the two X chromosomes present in each cell of female mammals is inactivated during early embryogenesis, to achieve dosage compensation with males (Avner and Heard 2001; Heard 2004). Initial steps of XCI involve a ‘counting process’, which senses the X chromosome/autosome ratio that restricts XCI to female embryos and, thereafter, the choice of which chromosome is inactivated (Morey et al . 2004).Skewed XCI leads to an expression of X-linked recessive disorders in females (Plenge et al. 2002; Mart´ınez et al. 2005; Renault et al. 2007). Another form of X-inactivation called meiotic sex chromosome inactivation (MSCI), takes place in males, during spermatogenesis and is a manifestation of the general meiotic-silencing mechanism (Turner 2007). In this study, we report the spontaneous abortion of a male foetus with an apparently methylated X chromosome, and propose that anomalous inactivation of its uniqueX chromosome could explain nonviability of the embryo and pregnancy loss. Therefore, we strongly suggest, as a follow up, that the methylation status of the X chromosome be tested in early spontaneous abortion of males in the absence of any other known genetic or nongenetic cause. |
Cita | Martinez, R., Bonilla Henao, V., Ramos, I., Sobrino, F., Lucas, M. y Pintado Sanjuán, E. (2008). May anomalous X chromosome methylation be responsible for the spontaneous abortion of a male foetus?. Journal of Genetics, 87 (3), 261-264. |
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