Hemochromatosis (Ch. 12) Flashcards
What is hemachromotosis?
↓ production of hepcidin = ↓ regulation of how much iron is absorbed and circulate = ↑ intestinal absorption of iron = ↑ iron deposits in body tissues = aggregation of iron = impedes cells –> eventual cell death
What is the inheritance pattern of hemachromotosis?
autosomal recessive
What is the gene associated with hemachromotosis?
HFE
What is the typical age of onset and why?
~40 y/o ; absorption of excess iron accumulates over a period of years
What are the main clinical manifestations for hemochromatosis?
abdominal pain, fatigue and arthralgias
What are the signs and symptoms of hemachromotosis?
- increased serum iron levels
- cirrhosis
- abnormal liver function tests
- diabetes
- hyperpigmentation of skin due to iron deposits
- hepatomegaly
What is cirrhosis?
degenerative liver disease; formation of scarring, fibrous tissue, and nodules
What factors can accelerate disease expression?
decreased liver function, alcohol abuse, and hepatitis
What is hepatitis?
inflammation of liver from toxins, autoimmune disorders or viruses
Why is hemochromatosis sex-influenced phenotype?
clinically expressed in men more than women due to regular iron loss in menstration
What chromosome is the HFE gene associated with hereditary hemochromatosis found on?
chromosome 6
What is a compound heterozygote?
individual having a combination of 2 mutations for the same gene
What are the 4 items measured in lab studies to determine hemochromatosis?
- serum iron level
- serum ferritin level
- total iron binding capacity
- transferrin saturation levels
What is serum iron level?
amount of free iron recently absorbed
What is serum ferritin level?
measures stored iron in ferritin
What is total iron binding capacity?
measures all proteins available to bind iron
What is transferrin saturation levels?
measure of transferrin (protein that transports iron)
What is hepcidin?
regulates how much iron we are taking in and how much of it is available to circulate
How can hemochromatosis cause diabetes?
iron buildup on pancreas = pancreatic damage = inability to respond to glucose levels
What are the 3 forms of treatment for hemochromatosis?
- Phlebotomy
- Liver transplant
- PCR
What are the other 3 types of hemochromatosis?
Type 2 = HJV or HAMP gene mutations (autosomal recessive) = more severe and earlier onset
Type 3 = TFR2 gene mutation (autosomal recessive) = Italian population and not as severe
Type 4 = SLC40A1 gene (autosomal dominant) = ferroportin-related iron overload
