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Open Access Open Badges Correspondence

DNA repair/replication transcripts are down regulated in patients with Fragile X Syndrome

Huichun Xu1, Mónica A Rosales-Reynoso2, Patricio Barros-Núñez2 and Emmanuel Peprah1*

Author Affiliations

1 Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, 12 South Dr. MSC 5635, Bethesda, MD 20892, USA

2 Centro de Investigación Biomédica de Occidente, Instituto Mexicano del Seguo Social, Sierra Mojada 800. Col. Independencia, Guadalajara, Jalisco, 44340, Mexico

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BMC Research Notes 2013, 6:90  doi:10.1186/1756-0500-6-90

Published: 11 March 2013



Fragile X Syndrome (FXS) and its associated disorders are caused by the expansion of the CGG repeat in the 5’ untranslated region of the fragile X mental retardation 1 (FMR1) gene, with disease classification based on the number of CGG repeats. The mechanisms of repeat expansion are dependent on the presence of cis elements and the absence of trans factors both of which are not mutually exclusive and contribute to repeat instability. Expansions associated with trans factors are due to the haploinsuffient or reduced expression of several DNA repair/metabolizing proteins. The reduction of expression in trans factors has been primarily conducted in animal models without substantial examination of many of these expansion mechanisms and trans factors in humans.


To understand the trans factors and pathways associated with trinucleotide repeat expansion we have analyzed two microarray datasets which characterized the transcript expression in patients with FXS and in controls.


We observed significant down regulation of DNA damage/repair pathway transcripts. This observation was consistent in both datasets, which used different populations. Within these datasets, several transcripts overlapped in the direction of association and fold change. Further characterization of these genes will be critical to understand their role in trinucleotide repeat instability in FXS.

Haploinsufficiency; FMR1; DNA repair/replication proteins