Clinical Perspectives on Hereditary Hemochromatosis

Abstract

Hereditary hemochromatosis (HH) comprises a group of inherited disorders of iron metabolism that can result in progressive iron overload, morbidity, and mortality, generally in adulthood. HFE-related HH is the most common type of HH and will form the core of this discussion. The discovery of new proteins and gene mutations has defined other types of HH, termed non-HFE HH. The regulatory protein hepcidin has a central role in iron homeostasis in these disorders. While the liver is the predominant organ of iron deposition and iron-overload-related disease in HFE-related HH, involvement of extrahepatic tissue can also result in morbidity and mortality if the disorder is not diagnosed before organ damage develops. This review traverses the road from HFE genotype to phenotype with a focus on clinical penetrance, modifier factors for disease expression, and current thoughts and controversies on HH diagnosis and screening.

Keywords:

• Cancer
• cirrhosis
• clinical expression
• genotype
• hemochromatosis
• hepatic iron concentration
• hepcidin
• HFE
• iron
• liver
• phenotype
• screening

Abbreviations
ALL	=	acute lymphoblastic leukemia;
ALS	=	amyotrophic lateral sclerosis;
BBB	=	blood brain barrier;
BMP	=	bone morphogenic protein;
FPN	=	ferroportin;
HAMP	=	hepcidin antimicrobial peptide;
HFE	=	hemochromatosis protein;
HH	=	hereditary hemochromatosis;
HIC	=	hepatic iron concentration;
HJV	=	hemojuvelin;
IREG1	=	iron-regulated transporter 1;
JH	=	juvenile hemochromatosis;
MHC	=	major histocompatibility complex;
MRI	=	magnetic resonance imaging;
MTP1	=	metal transport protein 1;
TFR1	=	transferrin receptor 1;
TFR2	=	transferrin receptor 2

Abbreviations
ALL	=	acute lymphoblastic leukemia;
ALS	=	amyotrophic lateral sclerosis;
BBB	=	blood brain barrier;
BMP	=	bone morphogenic protein;
FPN	=	ferroportin;
HAMP	=	hepcidin antimicrobial peptide;
HFE	=	hemochromatosis protein;
HH	=	hereditary hemochromatosis;
HIC	=	hepatic iron concentration;
HJV	=	hemojuvelin;
IREG1	=	iron-regulated transporter 1;
JH	=	juvenile hemochromatosis;
MHC	=	major histocompatibility complex;
MRI	=	magnetic resonance imaging;
MTP1	=	metal transport protein 1;
TFR1	=	transferrin receptor 1;
TFR2	=	transferrin receptor 2

Referee Dr. Kyle E. Brown, University of Iowa College of Medicine, Iowa City, Iowa, USA