The pathophysiology of OPMD involves the abnormal expansion of GCN trinucleotide repeats within the polyadenylate-binding protein nuclear 1 (PABPN1) gene, resulting in the accumulation of misfolded PABPN1 proteins and the formation of intranuclear inclusions within muscle cells. The gene discussed is PABPN1; the disease is oculopharyngeal muscular dystrophy.