A novel assay for evaluating fragile X locus repeats
Karl Adler1, J Kent Moore, Galina Filippov
1PerkinElmer Health Sciences, Inc., Molecular Diagnostics R&D, Waltham, MA 02451, USA.
The Journal of Molecular Diagnostics : JMD
|July 30, 2011
Summary
A new fragile X assay offers simple, high-throughput screening for FMR1 gene expansions. This fluorescent method may improve early detection of fragile X syndrome, aiding clinical diagnosis.
Area of Science:
- Genetics
- Molecular Biology
- Biochemistry
Background:
- Fragile X syndrome is caused by expansions of CGG trinucleotide repeats in the FMR1 gene.
- Current diagnostic methods can be complex and time-consuming, limiting high-throughput screening.
Purpose of the Study:
- To develop a novel, simple, and high-throughput assay for quantifying FMR1 trinucleotide repeats.
- To establish a microfluidic electrophoresis reflex test to differentiate fragile X mutation types.
Main Methods:
- Developed a novel assay using FMR1 gene amplification and a suspension-array hybridization method with fluorescent signals.
- Quantified trinucleotide repeats in amplicons to determine repeat numbers.
- Implemented a microfluidic electrophoresis reflex test for mutation classification.
Main Results:
- The assay successfully quantified FMR1 repeats in reference samples and 1008 dried blood spot samples.
- Identified 51 samples with potentially expanded alleles (≥45 repeats).
- Confirmed eight samples as premutations (≥55 repeats) using microfluidic electrophoresis.
Conclusions:
- The novel fluorescent hybridization assay is a straightforward, high-throughput method for FMR1 repeat quantification.
- This assay, with clinical validation, shows potential for screening fragile X syndrome.
- The microfluidic electrophoresis reflex test reduces the need for Southern blots in mutation differentiation.
