Hi all, 

I have this doubt which I couldn't sort out by myself. I started working with VCF files since one month only, so it might be that it's just that I didn't stumble on the right piece of literature yet. My VCF lines in the file have an INFO field which is like this:

    DP=20;VDB=0.000678823;SGB=-1.30291;MQ0F=0.5;AC=4;AN=4;DP4=0,0,19,0;MQ=3

Some of these Key=Value pairs are totally fine for me, the documentation is very clear. However, I can't find the description for all of them. For example: VDB, SGB, I don't know what they are. 

Where can I find such information? 
you should find this information in the VCF header, in a INFO field 

     grep '##INFO=<ID=VDB,' -m1  input.vcf

if it's missing: this is an error.