Platelet counts in HFE p.C282Y/p.C282Y and wt/wt post-screening clinical evaluation participants.

What is the context? Hemochromatosis is typically associated with inheritance of two copies of p.C282Y, a common mutation of the HFE gene on chromosome 6p that regulates iron absorption.Platelet counts, age, and serum levels of liver enzymes have been used to estimate risks of cirrhosis in adults with hemochromatosis.Lower platelet counts in Europeans are significantly associated with a mutation in CARMIL1, a gene on chromosome 6p close to HFE.Clinical and laboratory associations of normal platelet counts in adults with HFE p.C282Y/p/C282Y and wt/wt uncomplicated by cirrhosis are unreported.What is new? We studied normal platelet counts in 425 white adults who participated in a primary care-based hemochromatosis screening program. These participants did not have cirrhosis or other conditions that often influence platelet counts.Our analyses of 14 variables identified these significant positive associations with platelet counts, after adjustment for other variables: absolute neutrophil, lymphocyte, and monocyte counts and C-reactive protein levels; and these significant inverse associations: age, TS, and hemoglobin levels.What is the impact? Laboratory and clinical factors significantly associated with platelet counts in adults with HFE p.C282/p.C282Y or wt/wt are similar to those in persons unselected for HFE genotypes or hemochromatosis.It is unlikely that genes that influence platelet counts are closely linked to HFE on chromosome 6p.Adults with hemochromatosis and HFE p.C282/p.C282Y who have abnormal platelet counts should be evaluated for cirrhosis or non-iron platelet disorders.