Reevaluation of FMR1 Hypermethylation Timing in Fragile X Syndrome.

ABSTRACT: Fragile X syndrome (FXS) is one of the most common heritable forms of cognitive impairment. It results from a fragile X mental retardation protein (FMRP) protein deficiency caused by a CGG repeat expansion in the 5'-UTR of the X-linked FMR1 gene. Whereas in most individuals the number of CGGs is steady and ranges between 5 and 44 units, in patients it becomes extensively unstable and expands to a length exceeding 200 repeats (full mutation). Interestingly, this disease is exclusively transmitted by mothers who carry a premutation allele (55-200 CGG repeats). When the CGGs reach the FM range, they trigger the spread of abnormal DNA methylation, which coincides with a switch from active to repressive histone modifications. This results in epigenetic gene silencing of FMR1 presumably by a mul

SUBMITTER: Mor-Shaked H 

PROVIDER: S-EPMC5808132 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature