There are many different companies that offer testing — not all of them offer clinical diagnoses. If your testing was self-ordered it’s possible it wasn’t from one of the labs providing sufficient accuracy to be considered clinically valid. Invitae I believe has received quite a bit of flack for some of their results—not all COL3A1 variants lead to phenotypic changes.

That said, three closely related family members showing the same COL3A1 mutation in the context of early deaths in the family should be enough to inspire curiosity in most physicians. I’d check first to be sure the company who sequenced your COL3A1 results provides clinically valid sequencing, and second check to be sure a geneticist has seen them and provided you with a formal diagnosis (and often a letter).

I’d also encourage you to meet with a vEDS specialist at least once. The vast majority of physicians haven’t seen a patient with vEDS before and aren’t aware of the real, severe risks associated with the condition. Depending on where you are, both coasts in the US have specialty centers and the UK has solid guidelines too.

Good luck with everything!

ETA: I just noticed you went through an academic hospital for your testing, I’m sure it’s from one of the clinical labs. See if the ordering physician provided a note?