1Describe the structure of HbA
Consists of two alpha globin chains and two beta globin chains ( adult haemoglobin)
2Describe the structure of HbA2
Consists of two alpha globin and two delat globin chains
3How do thalaessemias arise?
Inherited mutations or deletions that reduce or dont produce alpha or beta globin chains; Causes ineffecting erythropoesis or haemolysis
4What sort of mutations can give rise to beta thalassemia?
Point ,mutations that affet RNA splicing, transcription or transolation
5What populations are affected by beta thalaessemia?
Mediterranean; Middle Est; North Africa; South Asia and Southeats Asia
6What popualations are affected by alpha thalaessemia?
Southeast Asia; Southern China; Mediterranaean; Middle East; Africa
7Describe the inheritance pattern of beta thalassaemia?
Autosomal recessive
8How does beta thalassaemia affect blood production?
Reduced beta globin synthesis causes excess unpaired alpha chains to accumulate damaging erythryoid precursors and red cells
9What are the clinical effects of untreated beta thalassaemia major?
Severe anaemia; Pallor; Jaundice; Growth failure; Hepatosplenomegaly; Bone marrow expansion
10What are the clinical features of beta thalassaemia?
Microcytic hypochromic anaemia; Fatigue; Pallor; Jaundice; Splenomegaly
11How is beta thalassaemia major treated?
Reegular red blood cell transfusion, iron chelation therpay, management of complications; HPST transplansts
12What are some consequences of transfusion iron overload?
Body cannot excrete large amounts of iron; Iron accumulations can damage the heart, liver, endocrine organs causing cardiomyopathy, liver firbosis or cirhosis, diabtes, hypothyroidsim
13How is a transfusion iron overload monitored?
Serial serum ferrtin measurements; Liver iron conc
14What are the aims of iron chelation therapy?
To bind excess iron and proote its excretion, reduce tissue iron accumulation, prevent organ damage and improve long termm survival and quality of life
15What are some examples of iron chelating drugs?
Deferasirox
16How often is a transfusion given to someone with beta thalassaemia major?
Usually every 2–5 weeks, depending on the patient's needs.
17What are the curative treatments of beta thalassaemia major?
Alligenic haematopoeitic stem cell transplant and selected gene therapies
18What is the mutation seen in sickle cell?
A missense mutation in the HBB gene causing glutamic acid to be replaced with valine
19What are the clinical consequences of sickle cell disease?
Chronic haemolytic anaemia, painful baso occlusive crises, acute chets syndrome, stroke, splenic dysfunction
20How is sickle cell disease managed?
Vaccination and infection prevention; Pencillin prophylaxis in young children; Hyroxyurea; Pain management; Transfusion
21How does hydroxycarbamide help with sickle cell disease?
It increases fetal haemoglobin which inhibits HbS polymerisation which reduces red blood cells from sickling and haemolysis
22How does an automated red cell exchange transfusion work?
Apherisis removes the patient’s red blood cells and replaces them with compatible donor red blood cells lowering the proportion of HbS
23What is haematopoeitic stem cell transplantaion?
A tretament that replaces a patients sickled blood with healthy donot stem cells which can establish normal blood cell production
24What are the aims of antenatal and neonatal screening for SCD and thalassaemia?
Identify affected babies and carriers; Enable early treatment and specialist follow up; Identify pregnancies at risk and provide infromed reproductive counselling and testing
25What are the options for couples with at risk pregnancies?
Genetic counselling; Prenatal diagnosis
26What test is done around 6 days after birth to test for sickle cell disease?
Heel prick test