John Kastelein

A careful, source-based search was not able to confirm the identity of the individual behind the contact details in the stub record (the personal Gmail/Facebook addresses and the "angel investor / seed" tag). No verifiable angel-investor profile — on AngelList/Wellfound, Signal (NFX), Crunchbase, a firm team page, or a personal site — could be tied to the name "John Kastelein" together with these email addresses. The initials implied by the email handle ("jr" — e.g., John R.) also do not match the most prominent public figure of this name (see below), so I have not merged the two records.

The most documented public individual named John Kastelein is Prof. John J.P. Kastelein, MD PhD FESC — but this appears to be a *different, biotech-focused* person, and the stub's personal email and "seed-stage angel" framing could not be verified against him. For transparency, his verifiable public profile is: Emeritus Professor of Medicine and former Chairman of the Department of Vascular Medicine at the Academic Medical Center (Amsterdam UMC), University of Amsterdam. He trained in internal medicine at the AMC and in lipidology/molecular biology at the University of British Columbia, Vancouver, and is a Fellow of the European Society of Cardiology.

On the venture side, that Prof. Kastelein serves as an Operating Partner at Forbion (advising on cardiovascular and metabolic-disease investments) and is Chief Science Officer of NewAmsterdam Pharma. He has co-founded several life-sciences companies (Xenon Pharma, uniQure, Dezima, NewAmsterdam Pharma) and is associated with firms such as BioGeneration Ventures. His work is in cardiovascular disease therapeutics and the genetics of dyslipidemia (award recognition includes the 2010 Dutch Heart Association €1M prize and the 2011 ZonMw Parel). This is a biotech founder/venture-partner profile, not a confirmed tech "seed angel," and it should not be assumed to be the person in the stub record without further verification.

• No verifiable, self-stated seed-stage angel thesis could be found for the individual in the stub record.
• The only publicly documented investing activity for a "John Kastelein" is life-sciences venture work by Prof. John J.P. Kastelein (Forbion; BioGeneration Ventures): cardiovascular, metabolic, and dyslipidemia-focused biotech — a distinct, unconfirmed match.