My first reaction was, “What? Do they mean the NHLBI 5400 Exome Sequencing Project? They only have 5,400 exomes not over 10,000! I wonder if there is some new control database I wasn’t aware of?” But being in journal-reading mode, I didn’t bother to look it up and went on.
I was pouring orange juice for my two year old this morning and pictures of perfect karyograms with attached diploid chromosomes came to my head for some reason. Aha! They are technically correct, and I suppose being very precise. They could also have said their variant wasn’t heterozygous or homozgyous in any of the the containing diploid chromosomes from the 5,400 exomes from NHLBI 5400ESP project. Or simply “It wasn’t present in over 5,400 exomes from the Exome Variant Server”. With the variant being on an autosomal chromosome, there was indeed two chromosomes where the mutation could have occurred per sample.
I don’t know. It seems a bit weird to claim your number of controls in terms of chromosomes rather than samples.
If you’ve seen this precedent before, I’d love to hear it.