Duplex PCR for Autosomal Dominant Spinocerebellar Ataxia Testing: A Nonradioactive Rapid Screening Method

Background: Current DNA diagnostic testing for spinocerebellar ataxias (SCAs) 1, 2, 3, and 6 involves four separate tests based on radioactively-labeled poly merase chain reaction (PCR). Although this approach allows accurate allele sizing, it also is time-consuming and requires manipulation with hazardous radioactive isotopes. Methods and Results: A rapid screening approach was developed based on a nonradioactive and duplexed PCR assay coupling SCA 1 and SCA 3 together and SCA 2 and SCA 6 together. This was achieved by designing new primers that amplify all normal and mutant alleles in nonoverlapping size ranges. A series of negative and positive samples previously tested with the single radioactively labeled PCRs was tested using the new duplex PCRs; 100% concordancy was achieved. Conclusion: This novel approach of nonradioactive, duplex PCRs for autosomal dominant spinocerebellar ataxias is a rapid, reliable, and cost-effective diagnostic screening approach that is suitable for laboratories with high sample load and/or laboratories seeking to reduce their use of radioisotopes.