A major objective of the project is to gather information needed to develop recommendations regarding possible primary care- or population-based screening for hemochromatosis. Estimating the burden of preventable illness from unrecognized hemochromatosis is one of the most important of these needs. Comparing the relative value and acceptability of diagnosis and screening by genotype vs phenotype is also important. In particular, differences by racial/ethnic group, age and other characteristics will need to be examined. Some of these issues, such as appropriate thresholds for transferrin saturation screening, may be resolved during the proposed study's planning phase, while others will constitute key research questions to be addressed by the study itself.