Porphyrias

Question 1

typical presentations of porphyria

Answer 1

blisters, fragility
hyper-pigmentation
solar urticaria
morphoea (reddish/purplish patches)

Question 2

enzyme thats deficient in PCT

what is it involved in the synthesis of?

Answer 2

uroporphyrinogen decarboxylase (UROD)
involved in synthesis of haem

Question 3

investigation for PCT

Answer 3

woods lamp

> red/pink skin fluorescence

Question 4

common factors associated with PCT

Answer 4

alcohol
oestrogen therapy
Hep C
haemachromatosis

Question 5

is PCT usually genetic or acquired

Answer 5

acquired

but 20% familial (mutation in UROD gene)

Question 6

management of PCT

Answer 6

treat underlying disease

Question 7

when does erythropoietic protophorphyria (EPP) usually develop?

Answer 7

childhood

Question 8

what causes EPP?

Answer 8

inherited deficiency of the enzyme ferrocheletase

Question 9

presentation of EPP

Answer 9

photosensitivity

hyper pigmentation

Question 10

Ix for EPP

Answer 10

quantitive RBC porphyrins
fluorocytes
transaminases

Question 11

“child who cries when exposed to light”

Answer 11

congenital erythropoietic protoporphyria

Question 12

management of congenital EPP

Answer 12

explain diagnosis with genetic counselling
6 mostly LFTs and RBC porphyrins
visible light protection measures

Question 13

what is there a build up of in PCT?

where does it build up?

Answer 13

uroporphyrinogen III synthase

builds up in the DEJ and when exposed to light > PCT

Question 14

risk of ? in PCT

Answer 14

liver cirrhosis

Question 15

which are neurotoxic

porphyrin precursors or porphyrins themselves

Answer 15

porphyrin precursors

Question 16

acute intermittent porphyria
deficieny of what enzyme?
leads to build up of what?

Answer 16

deficiency of PCG deaminase

build up of hydroxymethylbilane