Here, the authors establish CCG expansions in the 5’ untranslated region of ABCD3 as a cause of oculopharyngodistal myopathy (OPDM) in individuals of European ancestry and identify increased expression of expansion-containing ABCD3 transcripts as a possible disease mechanism underlying muscle degeneration. The gene discussed is ABCD3; the disease is oculopharyngodistal myopathy.