Features | Partner Sites | Information | LinkXpress
Sign In
RANDOX LABORATORIES
AB Sciex
SEEGENE

Novel Assay Developed for Evaluating Fragile X Locus Repeats

By Labmedica International staff writers
Posted on 19 Jan 2012
A novel fragile X locus repeat assay has been developed that is a simple and high-throughput method that, with clinical validation, may be suitable for screening.

The assay uses amplification of the fragile X mental retardation 1 (FMR1) trinucleotide repeat region, followed by a hybridization assay to quantify the number of repeats in the amplicons.

Scientists working in Molecular Diagnostics at PerkinElmer Health Sciences (Waltham, MA, USA) have developed the first repeat-counting assay that uses fluorescent signals rather than electrophoresis or mass spectrometry as the signaling mechanism. They also developed a simple microfluidic electrophoresis reflex test that uses the same amplicons and reduces the need for Southern blots to differentiate homozygous female normal samples from full mutations.

The assay was tested on DNA from 1,008 dried blood spot samples from pregnant women in their first trimester. Reflex testing was performed on the 2100 Bioanalyzer (Agilent Technologies; Santa Clara, CA, USA), a compact microfluidic capillary electrophoresis platform, using the Agilent Technologies DNA 7500 kit. Before electrophoresis, the polymerase chain reaction (PCR) products were first purified using the PureLink PCR kit (Invitrogen; Grand Island, NY, USA).

The hybridization assay identified 51 of those as potentially expanded alleles of equal to or greater than 45 repeats or as intermediate or higher in FMR1 repeat classification. Of these screen-positive samples, eight were confirmed by microfluidic electrophoresis as premutations consisting of equal to or greater than 55 repeats. Results for the PCR and hybridization assay are obtained in less time than an eight-hour shift, and the confirmation electrophoresis of screen-positive results takes approximately an additional two hours. All manipulations for the PCR and hybridization assay are performed in microplates and can be performed with a multichannel pipette for high throughput, with the prospect for straightforward automation.

The Luminex 200 (Austin, TX, USA) suspension array system reads the fluorescence results of the hybridization assay unattended. The ratios of fluorescent signals indicative of the repeat length are simple to calculate and embody into software, and no visual interpretations of electropherograms are needed for the approximately 95% of samples that will assay as screen assay negative in most screening settings. The authors concluded that their preliminary results suggest that the assay is a reasonable candidate for screening maternal samples for premutation yes-no status. With appropriate clinical validation, this assay will enable high-throughput, low-cost, low-investment screening. The study was published in the November 2011 issue of the Journal of Molecular Diagnostics.

Related Links:

PerkinElmer Health Sciences
Agilent Technologies
Invitrogen




GREINER-BIO-ONE
ADVANCED INSTRUMENTS
PURITAN MEDICAL
BioConferenceLive

Channels

Hematology

view channel

Blood Donations Screened for Viruses Using Multiplex Assay

A global healthcare company was chosen to partner the Japanese Red Cross (JRC; Tokyo, Japan) for nucleic acid screening of the nation's blood supply. Under the terms of the 7-year agreement, the healthcare company, Grifols (Barcelona, Spain) will provide the JRC with its newest automation platform, the Procleix Panther... Read more

Pathology

view channel

Gene Profile Predicts Risk of Bladder Cancer Recurrence

A genomic study has pinpointed several markers that identify bladder cancer patients at risk of recurrence and that may be indicators of overall survival status. Nearly half of patients with bladder cancer experience recurrences, so reliable predictors of this recurrent phenotype are needed to guide surveillance and treatment.... Read more

Industry News

view channel

Beckman Coulter and hc1.com Enter Strategic Partnership for Innovative Healthcare Cloud System

The diagnostics division of Beckman Coulter (Brea, CA, USA) and hc1.com (Indianapolis, IN, USA) have announced a partnership to bring an innovative healthcare cloud-technology system to clinical laboratories. The system, hc1.com's "Healthcare Relationship Cloud," helps turn large amounts of clinical data into actionable... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.