1. MGD Flashcards
What is amyloidosis?
Misfolding of proteins that forms insoluble forms of normally soluble proteins.
What is the result of amyloidosis in the brain?
Alzheimer’s or dementia.
What causes sickle cell anaemia?
An autosomal recessive mutation where alanine is replaced with thymine, so valine instead of glutamine - hydrophobic amino acid rather than hydrophilic. This forms hydrophobic knobs and pockets, haemoglobin polymerises to form a sickle shape that gets stuck in microvascualture.
What is a sickle cell crisis?
The sickle shape of haemoglobin blocks microvasculature and this causes pain and downstream anaemia.
What are sickle cell crises precipitated by?
By lowering O2 availability from smoking, cold, infection.
Why do sickle cell haemoglobin lead to anaemia?
The spleen breaks down red blood cells that are faulty so there is haemolytic anaemia.
How does sickle cell anaemia cause jaundice?
Haemolytic anaemia as spleen breaks down lots of red blood cels, so there is excess bilirubin released and jaundice.
What is a benefit of sickle cell anaemia in some countries?
Provides protection against malaria.
What is cystic fibrosis?
An autosomal recessive condition where there is a defective cystic fibrosis transmembrane regulator so impaired Na+/Cl- transport and thickened mucus.
What are the complications of cystic fibrosis?
Ciliary escalator is ineffective in the respiratory tract so bacteria isn’t cleared and infections occur. Pancreatitis from blocked pancreatic duct, fat digestion also stopped. Abnormally salty sweat. Vas deferens in males aren’t formed, causing infertility.
How is cystic fibrosis managed?
Prophylaxis for lung infection, lipase tablets for fat digestion, bypass vas deferens in males for sperm.
What is a-thalassaemia?
Where there is decreased or no a-gobin chains to form haemoglobin.
When does a-thalassaemia present and why?
Before birth as foetal haemoglobin (a2y2) needs a-globin chains too, so is affected.
What is B-thalassaemia?
Decreased or no B-globin chains to form haemoglobin.
When does B-thalassaemia present and why?
After birth as foetal haemoglobin doesn’t have any B-globin chains so isn’t affected.
How do thalassaemias cause anaemia?
Stable tetramers can’t form so there is less haemoglobin and decreased oxygen carrying capacity so symptoms of anaemia.
What is haemophilia A?
A recessive X linked condition where there is no/reduced factor VIII produced so no clotting.
How is haemophilia A treated?
Give recombinant factor VIII and avoid thrombolytics or blood thinners.
What is scurvy?
Vitamin C deficiency which means prolyl hydroxylase can’t convert proline to hydroxyproline, this means less H bonds and cross links form so collagen is ‘wobbly’.
What is Down’s syndrome?
Trisomy 21 from meiotic division error or Robertsonian translocation.
What are the features of Down’s syndrome?
Facial features, heart defects, impaired intelligence, leukaemia, early onset Alzheimer’s.
What is Edward’s syndrome?
Trisomy 18 from meiotic division error or Robertsonian translocation.
What are the features of Edward’s syndrome?
‘Rockerbottom’ feet, small lower jaw.
How long do those with Edward’s syndrome live?
1-2 weeks.
What is Patau’s syndrome?
Trisomy 13 from meiotic division error or Robertsonian translocation.
What are the features of Patau’s syndrome?
Congenital heart defects, cleft lip.
How long do those with Patau’s syndrome live?
Around 2.5 days.
What is Turner’s syndrome?
Monosomy X, there is a missing copy of a small autosomal region of the sex chromosome.
What are the features of Turner’s syndrome?
Short stature, heart defects, mild learning difficulties, neck webbing, infertility.
What is Klinefelter’s syndrome?
XXY, men with an extra X chromosome.
What are the features of Klinefelter’s syndrome?
Smaller testes so less testosterone production so lack of male sex characteristics, hypogonadism, infertility.
How can Klinefelter’s syndrome be treated?
Testosterone can help with some factors but can’t reverse infertility.
