OPMD is caused by a short trinucleotide repeat expansion encoding an expanded polyalanine tract in the polyadenylate binding-protein nuclear 1 ( PABPN1 ) gene .
B-DiseaseOrPhenotypicFeature O O O O O O O O O O O B-ChemicalEntity O O O B-GeneOrGeneProduct I-GeneOrGeneProduct I-GeneOrGeneProduct I-GeneOrGeneProduct O B-GeneOrGeneProduct O O O