DEVELOPMENT OF INNOVATIVE MOLECULAR AND SINGLE-CELL PREIMPLANTATION GENETIC DIAGNOSTIC AND SCREENING TESTS FOR DETECTING CGG-REPEAT EXPANSIONS IN THE FMR1 GENE

Abstract

Fragile X syndrome (FXS) is the most common inherited form of intellectual disability affecting 1 in 4000 males and 1 in 5000-8000 females. Molecular diagnosis and large-scale population-based sample screening of FXS are complicated due to the lack of simple polymerase chain reaction- or PCR-based tools that can be reliably used for detecting CGG-repeat expansions in the FMR1 (fragile X mental retardation 1) gene. We have successfully developed a methylation-specific triplet-primed PCR diagnostic assay, two triplet-primed PCR and melt curve analysis-based screening assays, and also have developed a reliable single-cell preimplantation genetic diagnostic tool for identifying individuals with FMR1 expansions. This thesis describes the utilization of well-characterised reference genomic DNA materials and patient DNA samples for the optimization and validation of the PCR-based assays that virtually addresses the major existing deficiencies in the molecular, single-cell preimplantation genetic diagnoses and screening of FXS.