HAEMOCHROMATOSIS

Question 1

What are the two types of iron that we absorb from our diet?

Where are they found?

How easily are they absorbed?

Answer 1

• Haem: found in meat, easily absorbed
• Non-haem: absorption aided by vitamin C

Question 2

Which iron storage protein is found both inside cells and in plasma?

Answer 2

Ferritin

Question 3

What is haemosiderin? Where was it found?

Answer 3

Iron storage compound

clumps of many molecules (including ferritin) found inside cells only

NOT measured in blood

Question 4

What is haemochromatosis?

what is the most common hereditary pattern?

Answer 4

Disease due to iron accumulation

autosomal recessive

Question 5

Which gene is abnormal in hereditary haemochromatosis? What chromosome is it found on? What does this cause? Why is this an issue for humans?

Answer 5

HFE gene → Human homeostatic iron regulator (HFE protein)

chromosome 6

► excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron stores. Humans, like most animals, have no means to excrete excess iron.

Question 6

Since it takes years for accumulation of iron in hereditary haemochromatosis, the condition usually presents in adulthood. Why do women present later?

Answer 6

Menstruation → lose iron every month

Question 7

What is the most common cause of secondary haemochromatosis?

Answer 7

Excessive blood transfusions

Question 8

List 6 organs where iron deposits in haemochromatosis and give the symptoms it causes in each

Answer 8

• Liver: hepatomegaly, cirrhosis, hepatocellular carcinoma
• Pancreas: diabetes
• Heart: cardiomyopathy
• Skin: bronze skin caused by combination of iron + melanin
• Joints: arthropathy
• Testes: atrophy, decreased libido, impotence

Question 9

What two things should people with haemochromatosis never consume? Explain why

Answer 9

• Alcohol: accelerates liver disease
• Vitamin C supplementation: increases non-haem iron absorption

HIGH YIELD

Question 10

Which two things would you expect to be raised in a blood test of someone with haemochromatosis?

Answer 10

Total iron

Ferritin

Question 11

Which three methods can be used to confirm the diagnosis of haemochromatosis?

Answer 11

• Genetic testing: C282Y mutation
• MRI: liver turns black from iron
• Biopsy: Prussian blue staining, blue granules from iron deposition

Question 12

What are the two main treatment options for the two types of haemochromatosis?

Answer 12

• Venesection (phlebotomy): first line in hereditary haemochromatosis
• Iron chelating agents: deferoxamine, used when venesection inappropriate e.g. in anaemic patients