Metabolic Dan Flashcards
T/F
Hereditary coproporphyria causes skin disease only
False
Skin + acute attacks
T/F
Porphyria cutanea tarda (PCT) is the most common type of porphyria
True
T/F
Acute intermittent porphyria (AIP) causes acute attacks only
True
no skin disease
AIP is alone in this group
Which porphyrias cause skin disease only?
Porphyria cutanea tarda (PCT)
Congenital erythropoietic porphyria (CEP)
Erythropoieic protoporphyria (EPP)
Which porphyrias cause skin disease and acute attacks?
Hereditary coproporphyria (HC) Variegate porphyria (VP)
T/F
Porphyrias all result from a total deficiency of one of the enzymes required for the biosynthesis of haem
False
from a partial deficiency of one of the enzymes
T/F
‘Bullous porphyrias’ includes all the skin disease causing porphyrias
False
EPP causes pain and erythema on sun exposure not bullae
T/F
All of the porphyrias except AIP cause cutaneous disease
True
T/F
Porphyrins absorb photons of infrared light, with wavelength peak at 408nm
False
visible violet light with peak at 408nm = the Soret band
T/F
Most types of porphyrias are inherited
True
T/F
Most patients with an inherited porphyria get symptoms eventually
False
Most remain asymptomatic
T/F
Accumulation of hydrophobic porphyrins leads to blistering skin disease on light exposure
False
Hydrophilic porphyrins accumulate in skin causing blistering
T/F
Accumulation of lipophilic protoporphyrins leads to an immediate cutaneous burning sensation after exposure to light, accompanied by erythema, and oedema
True
this occurs in EPP
T/F
Variegate porphyria causes immediate cutaneous burning sensation after exposure to light
False
In VP hydrophilic (uro- and copro-) and hydrophobic (proto-) porphyrins accumulate but the blistering skin disease predominates clinically
T/F
Acute porphyria attack is an acute and potentially fatal illness
True
T/F
In liver, a small proportion of available haem is incorporated into cytochrome P450 proteins
False
this is the main fate of haem in the liver
T/F
Acute porphyria attacks are caused by penicillins
False
not one of the main causes but can be true for individuals
What are the triggers of acute attakcs in porphyrias?
FIG BEANS Fever/ Infection Griseofulvin Barbiturates (o)Estrogen Alcohol Nutritional (fasting) Sulfonamides
Or 5 M’s Medication Menstruation(Oe) - esp luteal phase of cycle Maladie Malnutrition (fasting) Merlot (alcoholism)
What are the features of acute attacks in porphyrias?
6 P’s
Porphobilinogen deaminase deficiency and build up of Porphobilinogen
Precipitated by the 5 M’s
Pain in abdomen – in 95% of cases
Psychological symptoms – anxiety/agitation, hallucination, delirium, depression
Peripheral neuropathy – patchy numbness and paraesthesias
Pee Problems – dysuria, retention, Port-wine (dark purple) urine on standing/UV light
T/F
Haem is synthesised from Glycine + AcetylCoA
False
Glycine + SuccinylCoA
What are the substrates involved in the haem biosynthesis pathway?
‘Glycine & SuccinylCoA All Placed high in Urine Cup Produces Protoporphyrin 9’
Glycine + SuccinylCoA δ Aminolevulinic acid Porphobilinogen Hydroxymethylbilane Uroporphyrinogen (III) Coproporphyrinogen(s) Protoporphyrinogen IX Protoporphyrin IX (Haem)
T/F
The enzyme deficiency in PCT is Uroporphyrinogen decarboxylase (UROD)
True
T/F
The main substrate that builds up in PCT is coproporphyrinogen
False
Uroporphyrinogen (III)
What are the enzymes involved in the haem biosynthesis pathway?
‘All Sin All hyde, Porphos Uses Urine Cups on Poor Ferrets’ Ala Synthase Ala Dehydratase Porphobilinogen (PBG) deaminase (AIP) Uroporphyrinogen (III) synthase (CEP) Uroporphyrinogen decarboxylase(PCT) UROD Coproporphyrinogen oxidase (HC) Protoporphyrinogen oxidase (VP0 Ferrochelatase (EPP)