Porphyrias

Question 1

What are porphyrias?

Answer 1

Group of disorders that are due to a build up of chemicals in the body that produce porphyrins - happens when enzymes in the pathways for making haemoglobin don’t work

Question 2

Give 2 main types of porphyria?

Answer 2

Porphyria Cutanea Tarda

Erythropoietic Protoporphyria

Question 3

What are some general symptoms of porphyrias?

Answer 3

Blistering and skin fragility

Acute sunburn

Question 4

Which enzyme doesn’t work in porphyria cutanea tarda and which chemical builds up as a result?

Answer 4

Underactivity/deficiency of enzyme uroporhyrinogen decarboxylase leads to accumulation of uroporphyrinogen III in the liver

Question 5

What investigation can be done for porphyria cutanea tarda?

Answer 5

woods lamp - will show pink fluorescence

Question 6

What type of inheritance is linked to porphyria cutanea tarda?

Answer 6

Autosomal dominant

Question 7

Which enzyme doesn’t work in erythropoietic protoporphyria and which chemical builds up as a result?

Answer 7

Underactivity/deficiency of ferrochelatase leads to build up of protoporphyrin IX

Question 8

What type of inheritance is linked to erythropoietic protoporphyria?

Answer 8

X linked dominant

Question 9

Which organ can fail due to porphyrias and why?

Answer 9

Liver - this is where the chemicals build up in the different enzyme deficiencies

Question 10

A man presents with blistering on sun exposed skin that crusts over and heals leaving scars. He has excess hair on his face. What is the most likely differential diagnosis?

Answer 10

Porphyria cutanea tarda

Question 11

Which enzyme doesn’t work in acute intermittent porphyria?

Answer 11

PBG deaminase