haemoglobinopathies Flashcards
what shape are RBC
biconcave
what shape are RBC
biconcave
do RBC have nuclei
no
what is the function of RBC
transport oxygen which is found to haemoglobin
what molecule controls RBC levels and where is this molecule synthesised
Erythropoetein (EPO)
Kidney.
are the globin chains covalently bonded in haemoglobin
No.
what is the composition of haemoglobin in terms of the alpha and beta chains
2 alpha chains
2 beta chains
what is the function of glob in
protect harm from oxidation
renders the molecule soluble.
what is the composition of feral haemoglobin in terms of the alpha and gamma chains
2 alpha and 2 gamma chains
which 2 chromosomes control the glob in chains
chromosome 16- alpha
chromosome 11- gamma, delta and beta.
where is haemoglobin produced
3 places from inter to at birth
in the yolk sac -in utero
liver or spleen -10-12 weeks development in utero
bone marrow- end of gestation
define haemoglobinopathies
changes in globin genes or their expression leads to disease.
2 main types of haemoglobinpathies
structural-sickle cell (base substitution)
Thalassaemia- change in globin gene expression leads to reduced rate of synthesis of NORMAL globin chains.
plasma volume expands by how much in pregnancy
50%
red cell mass expands by how much in pregnancy
25%
what is defined as anaemia in the 1st and 3rd trimester
what is defined as anaemia in the second trimester
what happens to the number of white blood cells in pregnancy
Leukocytosis- increase in WBC
what happens to the platelet count during pregnancy
thrombocytopenia
platelet count is low- below the normal level but this is a physiological process.
causes of thrombocyopenia in pregnancy
production failure- severe folate deficiency.
Consumptive- gestational, pre-eclampsia and HELLP syndrome, AFLP, DIC e.g. in abruption TTP/HUS.
what makes pregnancy a prothrombotic state
platelet activation increase in procoagulant factors reduction in natural anticoagulants. reduction in fibrinolysis rise in markers of thrombin generation coagulation factors
how are haemoglobinopathies diagnosed/ detected.
Electrophoresis- for structural abnormalities.
Isoelectric focusing
High performance liquid chromatography.
Oxygen dissociation curve (p50, high affinity)
DNA analysis (genetic counseling, prenatal Dx)
Mass spectrometry
Kleihauer testing, Supravital staining, Sickle solubility
what is the substation which occurs in sickle cell anaemia
valine substituted for glutamine at postion 6 on B globin chain
why is the presentation of sickle cell only present 6 months after birth
foetal haemoglobin is present until 6 months after birth.