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Explain Output

All results generated by lohhlamod are stored in the directory specified by the --outdir flag.

Output Files

The output directory contains filtered alignments, the final statistical results, and intermediate data for visualization.

  • LOH result(*.loh.res.tsv): The primary output file containing LOH calls and copy number estimates. Each row corresponds to a specific HLA allele pair.

  • Filtered alignment(*.filt.bam): BAM files filtered by the minimum allowed mismatch events (controlled by the --min-ecnt option). These files represent the high-confidence reads used for the final LOH detection.

  • Intermediate objects(*.rds): R-serialized data files containing intermediate data table objects for each allele.

Deep dive analyses

These RDS files are highly valuable. While lohhlaplot command utilizes them to generate diagnostic plots (see Visulization page), you can also load them directly into an R session to perform custom downstream analyses, inspect raw statistics not available in the primary result, or create your own interactive visualizations.

LOH result schema

The main result file provides a detailed breakdown of copy number (CN) estimates and the statistical strength of the LOH call.

Column Description
HLA_A1_CN Estimated copy number for Allele 1. Upper and lower bounds are provided as _Upper and _Lower.
HLA_A2_CN Estimated copy number for Allele 2.
Pct_CN_Diff_Supporting_Bins % of bins showing a significant CN difference between Allele 1 and Allele 2.
HLA_A[1/2]_Median_LogR Median log-ratio of Tumor vs. Normal coverage across all bins for the respective allele.
HLA_A[1/2]_MM_Median_LogR Median log-ratio of Tumor vs. Normal coverage specifically at mismatch sites.
MM_LogR_Paired_Pvalue P-value from a paired test comparing the log-ratio difference between the two alleles at mismatch sites. This corresponds to the PVal legacy metric in HLALOH.
Median_BAF Median B-Allele Frequency (BAF) across all mismatch sites.
NUM_MM Total number of mismatch positions identified between the two alleles.
NUM_Bins Total number of 150bp (default) bins across the pairwise alignment.
NUM_MM_Bins Total number of bins that contain at least one mismatch site.
Pct_A[1/2]_Loss_Supporting_Bins % of bins showing a significant copy number loss for the respective allele.
HLAGene The HLA locus (e.g., HLA-A, HLA-B, HLA-C).
HLA_A[1/2] The specific nomenclature of the two alleles being compared.