Document output format with `--htp` flag for region-based regenie step 2

[dvg-p4]

The output format for gene/region-based regenie step 2 [edit: when using --htp] does not appear to be documented; https://rgcgithub.github.io/regenie/options/#output_1 just says it is "the same output format mentioned above."

With --build-mask sum, [edit: as mentioned in #336, --htp is intentionally ignored in this case, so] the columns have the same names as a single-variant run:

CHROM GENPOS ID ALLELE0 ALLELE1 A1FREQ N TEST BETA SE CHISQ LOG10P EXTRA

but they are used in ways that don't quite match the header. Empirically, it looks like:

• CHROM and GENPOS are the coordinates of the first variant in the region
• ID is <gene name>.<mask name>
• ALLELE0 is "ref"
• ALLELE1 is the mask name
• A1FREQ is presumably calculated after combining all alleles into a pseudo-allele as specified by --build-mask (right?)
• TEST is "ADD" (at least with all the input parameters I tried)
• EXTRA is usually NA; presumably it's that "additional column included to specify if Firth/SPA corrections failed."
• The rest of the columns are exactly what they say on the tin.

With [edit: --htp and] --build-mask max or --build-mask comphet however, the output format is completely different, and now includes the following columns:

Name    Chr     Pos     Ref     Alt     Trait   Cohort  Model   Effect  LCI_Effect      UCI_Effect      Pval    AAF     Num_Cases       Cases_Ref       Cases_Het       Cases_Alt       Num_Controls    Controls_Ref    Controls_Het    Controls_Alt  Info

As far as I can tell:

• Name is <gene name>.<mask name>
• Chr and Pos are again the coordinates of the first variant
• Ref is "ref"
• Alt is the mask
• Trait is the phenotype name
• Cohort is "TEST"
• Model is something like "ADD-WGR-FIRTH" (I get the gist but I'm not sure what the exact info conveyed here is?)
• There are now columns for Effect, LCI_Effect (?), and UCI_effect (?) instead of a single beta
• Pval is self-explanatory
• AAF I'm again assuming is calculated based on the combined pseudo-alleles
• Num_Cases, Cases_Ref, etc. are self-explanatory for binary traits, and for continuous traits the counts seem to be shoehorned in by considering everyone a "case" and leaving the "controls" columns NA
• Info seems to have a series of semicolon-separated name=value pairs, e.g. REGENIE_BETA=0.026852;REGENIE_SE=0.009518;MAC=160787.000000;SCORE=294.673996;SKATV=10948.247814;LOG10P=2.313457

I'd greatly appreciate if you could confirm or correct my assumptions here, fill in the gaps, and put all the information into the official documentation. A few "sample output" files could also be quite helpful, especially for designing workflows that take regenie's output as their input.

[tgbrooks]

I'm guessing that LCI_Effect and UCI_Effect lower and upper ends confidence interface on the beta (aka Effect). Would be nice to have documentation of these.

[joellembatchou]

Hi,

The details of the output with --build-mask are specified on the website:

What is the full command you are using? (it seems like you may be using the --htp option which is an internal dev command [not documented on the website] & has a different format from the native one)

Cheers,
Joelle

[dvg-p4]

@joellembatchou You are correct, we are using the --htp TEST option. This particular regenie pipeline actually predates my tenure at my company, so I'll ask around and see if anyone else remembers why we did that.

[dvg-p4]

My best guess here is that we specifically wanted the Cases_Ref / Cases_Het / Controls_Alt etc. statistics, which are not available in the standard, documented output format.

[dvg-p4]

So I guess my request is for there to be some documented way to get the Cases_Ref / Cases_Het / Controls_Alt etc. statistics out of regenie: either document the currently-available --htp, or add (an option for) these columns in the standard output format.