Caution Regarding the Interpretation of Homoallelism in Polyglutamine Multiplex Assays:

• Autores: Danielle C. Smith, Alina Esterhuizen, Jacquie Greenberg
• Localización: The Journal of molecular diagnostics, ISSN 1525-1578, Vol. 15, Nº. 5, 2013, págs. 706-709
• Idioma: inglés
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• Resumen

  • Spinocerebellar ataxia type 7 (SCA7) is an inherited dominant neurodegenerative disease caused by the expansion of a CAG repeat within the ATXN7 gene. Standard molecular diagnostic testing for SCA7 involves amplification of the region surrounding the CAG repeat via end-labeled PCR and subsequent capillary electrophoresis. In addition, multiplex methods exist that may be used to test for multiple polyglutamine spinocerebellar ataxias in a single assay. Herein, we used a SCA7 singleplex method to screen 111 individuals for whom the multiplex method detected a single normal allele. A total of six retested individuals (5.4%) were shown to have a pathogenic expansion at the ATXN7 locus. An additional triplet-primed PCR method was used to test the same cohort, and revealed no further disease-causing alleles. This study demonstrates the importance of using complementary methods to rule out apparent homoallelism during molecular testing for polyglutamine diseases.