Rare variants are uncommon in the population, while structural variants affect larger DNA segments: deletions, duplications or rearrangements. Although uncommon, some have a significant effect on health.
Genotyping chips, such as those used for Starter and Advanced, are not designed to detect them reliably. Ultra sequencing reads virtually the entire genome and is better at detecting rare variants. Your sequencing data may allow additional analysis of certain structural variants, subject to the method's limitations, but these are not currently interpreted in the reports; we may incorporate them as we validate their analysis. No finding of this kind replaces a confirmatory diagnostic test.