> For the complete documentation index, see [llms.txt](https://help.tso500software.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.tso500software.illumina.com/dragen-tso-500-guides/dragen-tso-500-v2.6/analysis-output/block-list.md).

# Block List

The block list represents high noise regions in the panel where false positive variant calls are likely produced. As a result, all positions in the gVCF are marked as Filter=excluded\_regions to indicate variant call results are not reliable in such regions.

The block list includes the following genes:

* HLA A
* HLA B
* HLA C
* KMT2B
* KMT2C
* KMT2D
* chrY
* Any position with VAF 1% occurrence in six or more of the 60 baseline samples.


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