Hemochromatosis (Ch. 12)

Question 1

What is hemachromotosis?

Answer 1

↓ 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

Question 2

What is the inheritance pattern of hemachromotosis?

Answer 2

autosomal recessive

Question 3

What is the gene associated with hemachromotosis?

Answer 3

HFE

Question 4

What is the typical age of onset and why?

Answer 4

~40 y/o ; absorption of excess iron accumulates over a period of years

Question 5

What are the main clinical manifestations for hemochromatosis?

Answer 5

abdominal pain, fatigue and arthralgias

Question 6

What are the signs and symptoms of hemachromotosis?

Answer 6

• increased serum iron levels
• cirrhosis
• abnormal liver function tests
• diabetes
• hyperpigmentation of skin due to iron deposits
• hepatomegaly

Question 7

What is cirrhosis?

Answer 7

degenerative liver disease; formation of scarring, fibrous tissue, and nodules

Question 8

What factors can accelerate disease expression?

Answer 8

decreased liver function, alcohol abuse, and hepatitis

Question 9

What is hepatitis?

Answer 9

inflammation of liver from toxins, autoimmune disorders or viruses

Question 10

Why is hemochromatosis sex-influenced phenotype?

Answer 10

clinically expressed in men more than women due to regular iron loss in menstration

Question 11

What chromosome is the HFE gene associated with hereditary hemochromatosis found on?

Answer 11

chromosome 6

Question 12

What is a compound heterozygote?

Answer 12

individual having a combination of 2 mutations for the same gene

Question 13

What are the 4 items measured in lab studies to determine hemochromatosis?

Answer 13

• serum iron level
• serum ferritin level
• total iron binding capacity
• transferrin saturation levels

Question 14

What is serum iron level?

Answer 14

amount of free iron recently absorbed

Question 15

What is serum ferritin level?

Answer 15

measures stored iron in ferritin

Question 16

What is total iron binding capacity?

Answer 16

measures all proteins available to bind iron

Question 17

What is transferrin saturation levels?

Answer 17

measure of transferrin (protein that transports iron)

Question 18

What is hepcidin?

Answer 18

regulates how much iron we are taking in and how much of it is available to circulate

Question 19

How can hemochromatosis cause diabetes?

Answer 19

iron buildup on pancreas = pancreatic damage = inability to respond to glucose levels

Question 20

What are the 3 forms of treatment for hemochromatosis?

Answer 20

• Phlebotomy
• Liver transplant
• PCR

Question 21

What are the other 3 types of hemochromatosis?

Answer 21

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