Acute Intermittent Porphyria Flashcards
Porphyrias a rare hereditary disease in which there is abnormal metabolism of the blood pigment haemoglobin. What is the incidence of this disease?
1 - 1/100,000
2 - 1/10,000
3 - 1/1000
4 - 1/100
3 - 1/1000
What type of genetic inheritance is Porphyrias?
1 - autosomal dominant
2 - X linked dominant
3 - autosomal recessive
4 - X-linked recessive
3 - autosomal recessive
Haemoglobin is the main protein in RBCs that carries O2. Which 2 components make up haemoglobin?
1 - bilirubin
2 - heme
3 - globin
4 - glucose
2 - heme
3 - globin
How many different globins are present on each haemoglobin?
1 - 1
2 - 2
3 - 4
4 - 8
2 - 2
- each haemoglobin has 2 alpha and 2 beta globin
- each globin has one haem group
Each haemoglobin is composed of 2 alpha and 2 beta globulins, each with their own haem group. How many heam groups are present on each globin?
1 - 8
2 - 6
3 - 4
4 - 1
4 - 1
There is one haem to every globin, means each haemoglobin has:
- 4 globin (2 alpha and 2 beta)
- 4 haem groups
Haem is composed of 4 pyrrole subunits forming a ring, and this structure is called a porphyrin. What molecule can be found in the middle of the haem?
1 - Fe2+
2 - Mg2+
3 - Na+
4 - Ca2+
1 - Fe2+
- this is what binds and carries O2 around the body
How many O2 molecules can each haemoglobin molecule carry?
1 - 16
2 - 8
3 - 4
4 - 1
3 - 4
- carries 1 in each haem
In a cell, which 2 places does the synthesis of haem begin?
1 - nucleus
2 - mitochondria
3 - cytosol
4 - rough endoplasmic reticulum
2 - mitochondria
3 - cytosol
- requires lots of enzymes
Haem synthesis begins in the mitochondria and the cytosol. In the cytosol which important enzyme is responsible for converting 4 molecules of porphobilinogen into hydroxymethylbilane?
1 - succinyl-CoA
2 - delta-ALA dehydratase
3 - porphobilinogen deaminase
4 - hydroxymethylbilane synthase
3 - porphobilinogen deaminase
- mutations is this is what we need to know about
- leads to reduces haem and increased metabolites from earlier stages in haem synthesis
In a rare autosomal recessive disease where the porphobilinogen deaminase is mutated, leads to a build up to metabolites that can become toxic to the body. Which of the following are the 2 toxic substances that build up?
1 - lactic acid
2 - porphobilinogen
3 - hydrogen peroxidase
4 - aminolevulinic acid
2 - porphobilinogen
4 - aminolevulinic acid
- both are toxic to the body
Do all patients with acute intermittent porphyria present with symptoms?
- no
Not all patients with acute intermittent porphyria present with symptoms. Do men or women present more with symptoms?
- women
- 10% young women present with symptoms, specifically if triggered, where haem production needs to be increased
Which of the following ate triggers that may cause symptoms in a patient with acute intermittent porphyria?
1 - excessive alcohol
2 - stavation
3 - medications that upregulate CYP450
4 - all of the above
4 - all of the above
- CYP450 contains haem and is required in the liver to metabolise drugs
The 2 metabolites that can build up in patients with acute intermittent porphyia are:
- porphobilinogen
- aminolevulinic acid
Of these 2 which is able to cross the BBB?
- aminolevulinic acid
- can affect autonomic, CNS and PNS function
Which of the following is NOT a CNS symptoms that can present in acute intermittent porphyia?
1 - delirium
2 - GIT dysmotility
3 - coma
4 - anxiety/psychosis
5 - seizures
2 - GIT dysmotility
- autonomic symptom