Idiopathic hemochromatosis: a study in a large Puerto Rican family.

We studied 13 first-degree relatives in a large family with an index case of idiopathic hemochromatosis to detect the relatives with evidence of iron overloading. Serum iron, total iron binding capacity (TIBC), and serum ferritin levels were measured in all family members. We also performed HLA typing to identify the relatives who are homozygous with the proband and genetically predisposed to develop the disease. The family was composed of the parents and 12 siblings including the index case. The mean age of the siblings was 25 years. None presented with evidence of iron overload by the iron biochemical tests. HLA typing demonstrated six homozygous siblings with the proband. In separate analysis these siblings did not present abnormalities in any of the iron biochemical tests. These homozygous relatives were followed for one year after initial evaluation and none presented abnormalities in the iron studies during this period. These results are contradictory to other previous studies done in families with idiopathic hemochromatosis. The most feasible explanations for these findings are the young age of these siblings and the predominance of females among them. We consider that these homozygous relatives must be followed for their life-times with iron studies to detect a possible increase in iron stores as expected in later ages.