Which of the following is deficient in patients with hereditary angioedema?
Correct Answer A: Hereditary angioedema - C1-INH deficiency.
Hereditary angioedema:
Hereditary angioedema is an autosomal dominant condition associated with low plasma levels of the C1 inhibitor (C1-INH) protein. C1-INH is a multi-functional serine protease inhibitor - the probable mechanism behind attacks is uncontrolled release of bradykinin resulting in oedema of tissues.
Investigation:
Symptoms:
Management:
Patients with deficiencies of which one of the following complement proteins are most predisposed to disseminated meningococcal infection?
Correct Answer E: Whilst C3 deficiency is associated with recurrent bacterial infections, C5 deficiency is more characteristically associated with disseminated meningococcal infection.
Complement deficiencies:
Complement is a series of proteins that circulate in plasma and are involved in the inflammatory and immune reaction of the body. Complement proteins are involved in chemotaxis, cell lysis and opsonization.
C1 inhibitor (C1-INH) protein deficiency:
C1q, C1rs, C2, C4 deficiency (classical pathway components):
C3 deficiency:
C5 deficiency:
C5-9 deficiency:
Which of the following conditions is inherited in an autosomal recessive fashion?
Correct Answer D: Autosomal recessive conditions are 'metabolic' - exceptions: inherited ataxias Autosomal dominant conditions are 'structural' - exceptions: hyperlipidaemia type II, hypokalaemic periodic paralysis.
Autosomal recessive conditions:
Autosomal recessive conditions are often thought to be 'metabolic' as opposed to autosomal dominant conditions being 'structural', notable exceptions:
The following conditions are autosomal recessive:
*This is still a matter of debate and many textbooks will list Gilbert's as autosomal dominant
Which one of the following occurs during reverse transcriptase polymerase chain reaction?
Correct Answer D: PCR: Polymerase chain reaction (PCR) is a molecular genetic investigation technique. The main advantage of PCR is its sensitivity: only one strand of sample DNA is needed to detect a particular DNA sequence. It now has many uses including prenatal diagnosis, detection of mutated oncogenes and diagnosis of infections. PCR is also extensively used in forensics. Prior to the procedure it is necessary to have two DNA oligonucleotide primers.
These are complimentary to specific DNA sequences at either end of the target DNA Initial prep:
The following cycle then takes place:
The above cycle is then repeated, with the amount of DNA doubling each time
Reverse transcriptase PCR:
Which of the following is true regarding rheumatoid factor?
Correct Answer A: Rheumatoid factor is an IgM antibody against IgG.
Rheumatoid factor: Rheumatoid factor (RF) is a circulating antibody (usually IgM) which reacts with the Fc portion of the patients own IgG.
RF can be detected by either:
RF is positive in 70-80% of patients with rheumatoid arthritis, high titre levels are associated with severe progressive disease (but NOT a marker of disease activity).
Other conditions associated with a positive RF include:
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