Rapid and reliable molecular diagnosis of oculopharyngeal muscular dystrophy: a cost-effective alternative for PABPN1 gene (GCN)n repeat analysis.

Oculopharyngeal Muscular Dystrophy (OPMD) is a late-onset autosomal dominant disorder caused by an abnormal (GCN)n trinucleotide repeat expansion in exon 1 of the polyadenylate-binding protein nuclear 1 (PABPN1) gene. This expansion increases the polyalanine tract from a normal 10 to 11-18 repeats, leading to progressive muscle weakness. We evaluated the advantages of fragment analysis via a capillary electrophoresis system using a Gelbot device as a cost-effective alternative to Sanger sequencing for determining (GCN)n repeat numbers. A total of 90 genomic DNA samples primarily analyzed by Sanger sequencing were submitted to the above-mentioned capillary electrophoresis. This showed full concordance in the detection of expanded alleles. Compared to DNA sequencing, fragment analysis offered a faster turnaround time, a simpler workflow, and more straightforward result interpretation. Notably, this method requires less initial expenditure on instruments and avoids the need for fluorescently labelled primers and other reagents, which significantly reduces implementation costs. In conclusion, capillary electrophoresis-based fragment analysis provides a reliable, rapid, and accessible method for PABPN1 screening. It represents a practical diagnostic alternative for OPMD, particularly in laboratories with limited resources.