Funding Support and Author Disclosures In-house funding at each institution was used to cover effort of contributors for data collection and entry. The creation and the maintenance of the REDCap database and support of a study coordinator for bulk data entry was provided in house by Dr Cuchel at the University of Pennsylvania. Support of the registry coordinators (Drs Schonck and Tromp) was provided in house by Dr Hovingh at Amsterdam UMC. The HICC is an investigator-initiated project supported by funding from the academic institutions of the collaborators. The European Atherosclerosis Society provided funding to support a registry coordinator. Dr Blom has received research grants from Amgen, Amryt, AstraZeneca, Sanofi, and Regeneron; has received lecture fees and personal fees from Amgen, Amryt, Merck Sharp & Dohme, Sanofi-Aventis, and Novartis; participation in the advisory board for Amryt (Chair of the LOWER study steering committee); and serves as a member of the executive committee of the Lipid and Atherosclerosis Society of South Africa and the International Atherosclerosis Society. Dr Catapano has received honoraria, lecture fees, or research grants from Aegerion, Akcea Therapeutics, Amarin, Amgen, Amryt Pharma, AstraZeneca, Daiichi-Sankyo, Esperion, Ionis Pharmaceutical, Medscape Education, Menarini, Merck, Mylan, Novartis, PeerVoice, Pfizer, Recordati, Regeneron, Sanofi, The Corpus, and Viatris. Dr Cuchel has received institutional research funding from Regeneron Pharmaceuticals and Regenxbio; and has received honoraria from Chiesi, Regeneron, and Ultragenyx. Dr Freiberger was supported by the project National Institute for Research of Metabolic and Cardiovascular Diseases (Programme EXCELES, ID Project No. LX22NPO5104)--Funded by the European Union--Next Generation EU; has received honoraria from Novartis, Sanofi, and Amgen; and has served on the advisory board for Sobi and Medison. Dr Groselj has received lecture fees from Novartis, AstraZeneca, and Ultragenyx. Dr Harada-Shiba has received research grants from the Japan Agency for Medical Research and Development; and has received honoraria and lecture fees from Amgen, Novartis, Ultragenyx, MEDPACE, Protocera, Kowa, Kaneka Medics, Boehringer Ingelheim, Sanofi and BML. Dr Hovingh has received research grants from the Netherlands Organization for Scientific Research (vidi 016.156.445), CardioVascular Research Initiative, European Union, and the Klinkerpad fonds; has received institutional research support from Aegerion, Amgen, AstraZeneca, Eli Lilly, Genzyme, Ionis, Kowa, Pfizer, Regeneron, Roche, Sanofi, and The Medicines Company; has received speakers bureau and consulting fees from Amgen, Aegerion, Sanofi, and Regeneron until April 2019 (fees paid to the academic institution); is a part-time employee at Novo Nordisk; and has stock in Novo Nordisk. Dr Iatan has served on advisory boards for Amgen, HLS Therapeutics, and Novartis; and has received honoraria from Novartis and Sanofi-Aventis. Dr Kayikcioglu has received honoraria from Abbott, Abdi Ibrahim, Chiesi, LIB Therapeutics, Novartis, Novo Nordisk, TR-pharma, and Ultragenyx; has received research funding from Amryt Pharma; and has participated in clinical trials with Amgen, Ionis, LIB Therapeutics, Novartis, and Novo Nordisk, during the past 3 years. Dr Klingel has received research funding and consulting fees from Diamed and Asahi Kasei Medical. Dr Raal has received advisory board fees and lecture fees from Amgen, Sanofi-Aventis, Regeneron Pharmaceuticals, Novartis, and LIB Therapeutics. Dr Reeskamp is cofounder of Lipid Tools; and has received lecture fees from Novartis, Ultragenyx, and Daiichi-Sankyo. Dr Wiegman has received lecture fees and research support for pharmaceutical trials of lipid-lowering agents from Amgen, Chiesi, Merck Sharp & Dohme, Esperion, Novartis, Regeneron Pharmaceuticals, Sanofi, Silence Therapeutics, and Ultragenyx, which were received by the department. Dr Roeters van Lennep’s department has received a research grant from Novartis. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.