Iron Overload (cont.)
Dennis Lee, MD
Dennis Lee, MD
Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.
In this Article
How is hereditary hemachromatosis inherited?
Hereditary hemochromatosis is an autosomal recessive disorder, which means an individual has the possibility of developing iron overload only if he/she inherits abnormal genes from both parents. (An autosomal recessive disorder is different from autosomal dominant disorder in which individuals can develop disease by inheriting an abnormal chromosome from only one parent.)
The human body is composed of trillions of cells. Inside the inner core (nucleus) of each cell are chromosomes. Every human cell has two sets of 23 chromosomes (total of 46 chromosomes). Each set is inherited from one parent. Chromosomes contain DNA that carries genes that govern all bodily functions including cell metabolism, appearance, height, intelligence, hair and eye color, and other physical traits. Defects in DNA (also called mutations) are passed from one generation to the next, and sometimes can cause diseases.
There are primarily two mutations associated with hereditary hemochromatosis; C282Y and H63D. The numbers 282 and 63 designate the location of the defects on the HFE gene located on chromosome number 6. An individual who inherits two C282Y mutations (one from each parent) are called C282Y homozygotes, and he/she has a significant chance of developing hemochromatosis. In fact, C282Y homozygotes account for 95% of cases of hereditary hemochromatosis. Patients who inherit one C282Y mutation from one parent and another H63D mutation from another parent are called compound heterozygotes. They account for another three percent of the cases of hereditary hemochromatosis.