Why are targets listed more than once in the output files?

Tapestri Designer uses VarSome to resolve HGVS IDs for the variant to a region. Once resolved, these regions are then used to design the panels.

A variant can be generated by multiple mutations. For example, a mutation of 1, 2, or 3 bases of a codon or base can change at any one of the 3 positions in the codon. Thus, a variant can be resolved to multiple regions, and all these regions are listed in the output files. For example, the variant NRAS:T148S is resolved to the following 2 regions:

Because these regions are very close together, they would be covered by a single amplicon.

In the case of genes where multiple transcripts exist, the same variant can be resolved to two very different regions. For example, TP53:Y181C is resolved to:

If the regions are far enough apart, two amplicons may be needed to cover the regions. If so, it is better to review the design and add the transcript ID to the HGVS ID when submitting the targets to Tapestri Designer. Thus, if you are interested in the first region, submit the target as NM_001276760.2(TP53):Y181C and NM_001276699.2(TP53):Y181C for the second region.