Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

1.2 Health Science > Haemochromotosis > Flashcards

Haemochromotosis Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Where is iron acquired from

A

Food - essential mineral
HAEM - animal meat
NON-HAEM - legumes, leafy greens, fortified foods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is ferritin? Is it soluble?

A

Water soluble Fe storage protein. low serum ferritin = release of transferrin from liver to bring levels back up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is haemosiderin

A

Water-insoluble Fe storage complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is transferrin?

A

a carrier protein found in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is excess iron excreted?

A

haem via bile, faeces in the form of stercobilin, urine in the form of urobilin, menstruation, intestinal exfoliation, skin desquamation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

why is iron recycling important in the body?

A

It is important because dietary iron is often 10 times less than what is required- you need 20mg daily but often only 1-2mg is absorbed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens in the body when iron concentration is increased?

A
  • increased ferritin concentration
  • HFE protein (human homeostatic iron regulator) up-regulates hepcidin in a signalling pathway. Hepcidin decreases dietary iron absorption
    -Hepcidin downregulates ferroportin (a transmembrane protein) which transports iron in and out of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is hereditary haemochromotosis transmitted?

A

It is an inherited condition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is haemochromotosis

A

chronic excessive intestinal absorption of dietary iron which results in a pathological increase of iron stores in tissues and organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the symptoms of HH?

A

Fatigue and malaise (discomfort), joint pain, abdominal pain, skin discoloration (bronze or grey), arrythmia, erectile dysfunction or decreased libido, amenorrhoea (lack of menstruation) and symptoms of endocrine impairment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Is HH dominant or recessive?

A

typically autosomal recessive but depends on the mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which types of HH are autosomal recessive?

A

types 1-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of HH is autosomal dominant

A

Type 4 (ferroportin disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Write a note on Type 1 HH

A

Caused by a cysteine to tyrosine substitution at amino acid 282 (C282Y) or ahistidine to aspartate substitution at amino acid 63 (H63D) on the HFE gene that codes the HFE protein. C282Y (the position on the HFE protein) is the most prevalent type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Write a note on HH Type 2

A

Also known as juvenile haemochromotosis. Is caused by mutations in the HJV gene that code for an iron regulatory protein hemojuvelin. Symptoms usually develop earlier in life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Write a note on HH Type 3

A

It is caused by mutations in the TfR2 gene that codes for transferrin receptor protein 2. This mediates cellular uptake of iron, and when it is inactive, it results in iron overload

17
Q

Write a note on Type 4 HH

A

known as ferroportin disease and is quite rare. Caused by mutations in the SLC40A1 gene that codes for ferroportin. At least 39 mutations in the SLC40A1 gene have been identified in patients with ferroportin diease.

18
Q

What is the pathogenesis of Type 1?

A
  • Hepcidin deficiency and iron absorption not reduced in response to increased iron levels
  • ferroportin is not downregulated and iron is still exported to blood
  • increased ferritin
  • transferrin saturation
19
Q

What is the pathogenesis of Type 2 HH

A
  • Haemojuvelin regulates hepcidin
  • mutated HJV = dysregulated hepcidin = inability to reduce serum iron concentration
  • hepcidin deficiency
20
Q

what is type 3 HH pathogenesis

A
  • Transferrin receptor protein 2 (TfR2) mediates cellular update of transferrin bound iron
  • so the mutated TfR2 gene = deficiency in TfR2 protein and = inability to reduce serum iron concentrations
21
Q

What is the pathogenesis for type 4 HH

A
  • Ferroportin is a transmembrane protein that transports iron in and out of cells/tissues
  • a Mutated SLC40A1 gene = excessive cellular iron
22
Q

What are the complications of HH

A

-Splenic and liver iron overload + dysfunction. May develop fibrosis and cirrhosis- hepatocellular carcinoma
- diabetes (pancreatic iron deposition)
- arrhythmia and congestive heart failure (iron deposits in muscle fibres and conductivity system)
- hypogonadism/amenorrhoea- endocrine dysfucntion
-skin hyperpigmentation from haemosiderin and melanin deposition
- osteoporosis
- anaemia in type 4 HH
-Foodborne infection - raw bivalves

23
Q

HH epidemiology

A

Really common in Northern Europe. Type 1 mostly confined to those of Northern Europe descent . Type 1-3 manifests in adulthood, but Juvenile HH can become apparent between ages 10-30. male to female ratio 3:1:8- women become symptomatic later in life (menstruation)

24
Q

HH treatment- Phlebotomy

A

Phlebotomy- Induction: blood removed frequently until serum iron levels are normal (takes 12 months), or Maintenance: blood taken quarterly or biannually to manage iron levels. Life long therapy.

25
Q

HH treatment- Chelation therapy

A

Chelation therapy used when phlebotomy is not possible. Chelating agent binds to iron and is excreted via faeces or urine. Iron chelation with desferrioxamine is used in Ireland. Side effects such as dizziness, sensory impairments, muscle cramps, thrombocytopenia, tachycardia

26
Q

HH treatment - Therapeutic erythrocytapheresis

A

Involves the removal of erythrocytes rather than whole blood. Use of cell separator. Data shows this therapy = x4 reduction of phlebotomy sessions. However phlebotomy is cheaper and should be first line therapy

27
Q

HH treatment- diet

A

avoid foods fortified with iron, alcohol, raw bivalves (oysters/clams)

28
Q

What haemoglobin level would suggest haemochromotosis?

A

> 18 g/dL

29
Q

What is used to diagnose haemochromatosis?

A

Biochemistry: Increased transferrin saturation & ferritin levels
Haematology: FBC - increased Hb, MCH, & MCHC
Histopathology: iron deposits in hepatocytes - Perl’s Prussian Blue stain haemosiderin granules blue
Molecular Biology: confirm diagnosis

30
Q

What causes absolute malabsorption of iron?

A

Coeliac disease

31
Q

What cause relative malabsorption of iron?

A

Pregnancy & puberty

32
Q

How is Fe recycled?

A

Senescent RBCs broken down by macrophages in liver & spleen - releases haem which binds to transferrin - 80% to bone marrow for erythropoiesis

33
Q

What is the other 20% of Fe used for?

A

Respiration & DNA synthesis

1.2 Health Science (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions