Snpeff: clarification on gene fusion annotation

Question

[laura.mannarino]

Hi, I have a question about brakends (BND). They are sometimes annotated (INFO field) as |gene_fusion|GENE_NAME1&GENE_NAME2| and this is clear to me, however how can I interpret the same annotation with only one gene, for example |gene_fusion|GENE_NAME|?

Examples:

]CHR13:21750661]C|gene_fusion|HIGH|DDX10|ENSG00000178105

]CHR13:21750661]C|bidirectional_gene_fusion|HIGH|DDX10&SKA3|