ɪn fˈoːɹ ʌv ðiːz fˈæmɪliz, dˌuːplɪkˈeɪʃən ʌvðə bɹˈækjuːɹi dʒˈiːn wʌz fˈaʊnd təbi ɹᵻspˈɑːnsᵻbəl fɔːɹ kˈɔːzɪŋ kɔːɹdˈoʊmə.
In four of these families, duplication of the brachyury gene was found to be responsible for causing chordoma.