A majority of fragile X males with methylated, full mutation alleles have significant levels of FMR1messenger RNA
- aDepartment of Biological Chemistry, University of California, Davis, School of Medicine, One Shields Avenue, Davis, CA, USA, bMIND Institute, University of California, Davis, School of Medicine, Davis, CA, USA, cDepartment of Pediatrics, University of California, Davis, School of Medicine, Davis, CA, USA, dKimball Genetics Inc, Denver, CO, USA
- Dr P J Hagerman, pjhagerman{at}ucdavis.edu
- Revised 26 March 2001
- Accepted 26 March 2001
Abstract
FMR1 mRNA levels were determined in peripheral blood leucocytes for 48 fragile X males with methylated, full mutation alleles that are resistant to cleavage by methylation sensitive enzymes. Using quantitative (fluorescence) RT-PCR, we observed that more than half of these males produceFMR1 mRNA, with some mRNA levels approaching those found in normal subjects. In none of the samples analysed was there any evidence of premutation alleles. These results suggest that the assumed relationship between enzyme resistance andFMR1 gene silencing may not be generally valid. Despite the presence of FMR1 mRNA in some subjects, no FMRP production was detected by either immunocytochemistry or western blotting. The low/absent FMRP levels are probably a reflection of a post-trancriptional effect such as a defect in translation.
