Iron overload (hemochromatosis) is a condition which causes the intestines to take too much
iron into the body from food or pills. The extra iron can build up in the liver, heart,
joints, pancreas, sex organs, and other organs. Patients with iron overload can feel well
initially, but the iron will eventually damage organs and may lead to an early death. The
condition is believed to be passed down from generation to generation. Many studies have
been conducted on the condition as it affects Caucasian Americans, few have addressed the
condition in African Americans.
Researchers believe it is important to find out as much as possible about the iron overload
in African Americans. The goal of this study is to determine the pattern of inheritance of
primary iron overload in African American families and to identify the genetic defect
causing the condition.
The study will use various tests from simple blood testing (transferritin saturation and
serum ferritin levels) to complex genetic tests (segregation analysis and polymerase chain
reaction [PCR]). The tests will help researchers deterimine iron levels in the blood,
presence of antigens that may help trace inheritance, and detect changes in genes that are
known to cause iron overload in Caucasians.
The study may not directly benefit the patients participating in it. However, this study
may lead to improved methods to diagnose iron overload in the African American population as
The purpose of this project is to determine the pattern of inheritance of primary iron
overload in African American families and to identify the genetic defect. The iron status
of index subjects and family members will be determined by measuring transferrin saturation
and serum ferritin, and the genetic pattern will be studied with segregation analysis. The
chromosomal localization of the iron-loading locus will be pursued by determining HLA
haplotypes, by testing for HFE gene mutations, by sequencing portions of genes for molecules
involved in iron metabolism, by analyzing polymorphisms in these genes by PCR, by employing
molecular methods to screen the genome, and by testing for linkage to iron phenotype with
lod scores. Loci for proteins important in iron metabolism will be examined as candidate
Index subjects as well as male and female first and second degree family members, greater
than 5 years of age, of index subjects with iron overload.
In some cases, more distant family members will also be studied.
No patients less than or equal to 5 years old.