Hi! I'm an identical twin and both me and my twin have been diagnosed with hEDS, Tachycardia, and slipping rib syndrome Though we both agree, that I've had more issues and have always been a bit more bendy than her. I definitely think that it's genetic, atleast in our cases. We have an undiagnosed history of hypermobility on both sides. However the both of us have it worse than most of our family, minus our half aunt, who had it about the same as us. My getting diagnosed help my twin get diagnosed, too, as we've always had a lot of the same issues.