1 Page 1 This article is protected by copyright. All rights reserved. Title: The natural history of HFE simple heterozygosity for C282Y and H63D: a prospective 1 twelve year study 1 2 3 Running title: HFE C282Y and H63D simple heterozygosity 4 5 Sophie G. Zaloumis 1 (sophiez@unimelb.edu.au) 6 Katrina J. Allen 2,3,4 (Katrina.Allen@rch.org.au) 7 Nadine A. Bertalli 2 (nadine.bertalli@mcri.edu.au) 8 Lidija Turkovic 1 (lidija78@yahoo.com) 9 Martin B. Delatycki 2,3,5 (martin.delatycki@vcgs.org.au) 10 Amanda J. Nicoll 6 (amandajnicoll@westnet.com.au) 11 Christine E. McLaren 7 (cmclaren@uci.edu) 12 Dallas R. English 1,8 (d.english@unimelb.edu.au) 13 John L. Hopper 1 (j.hopper@unimelb.edu.au) 14 Graham G. Giles 1,8 (Graham.Giles@cancervic.org.au) 15 Gregory J. Anderson 9 (Greg.Anderson@qimr.edu.au) 16 John K. Olynyk 10 (jolynyk@meddent.uwa.edu.au) 17 Lawrie W. Powell 9,11 (Lawrie.Powell@qimr.edu.au) 18 Lyle C. Gurrin 1 for the HealthIron Study Investigators* (lgurrin@unimelb.edu.au) 19 20 1 Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global 21 Health, The University of Melbourne, Victoria, Australia 22 2 Murdoch Childrens Research Institute, Victoria, Australia 23 3 Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Victoria, 24 Australia 25 4 Department of Gastroenterology, Royal Children’s Hospital, Victoria, Australia 26 This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/jgh.12804 Accepted Article