Major forms of Hb: HbA = 2 Alpha chains & 2 Beta Delta Gamma Theta( Beta, Delta, Gamma, Theta ) chains HbA2 = 2 Alpha chains & 2 Delta Beta Gamma Theta( Delta, Beta, Gamma, Theta ) chains HbF = 2 Alpha chains & 2 Gamma Delta Beta Theta( Gamma, Delta, Beta, Theta ) chains
The most abundant Hb in the normal human body is HbA HbA2 HbF( HbA, HbA2, HbF )
Alpha genes lie on chromosome 16. There are 4 2 6( 4, 2, 6 ) alpha genes per cell (2 1 3( 2, 1, 3 ) on each chromosome) Beta genes lie on chromosome 11. There are 2 4 6( 2, 4, 6 ) beta genes per cell (1 2 3( 1, 2, 3 ) on each chromosome)
Adult levels of HbA are typically achieved by 12 months 3 months 18 months 2 years( 12 months, 3 months, 18 months, 2 years ) of age
Haemoglobinopathies are hereditary conditions which affect the synthesis of chains, thus affecting haemoglobin production.
Haemoglobinopathies whereby there is a decreased rate of globin chain synthesis are called
Reduced rate of production of alpha globin chains is known as Reduced rate of production of beta globin chains is known as
Thalassaemias lead to microcytic macrocytic( microcytic, macrocytic ) anaemia
❌ = 1 or 2 alpha genes missing (i.e -α/αα OR -α/-α) ❌ = 3 alpha genes missing (i.e. (--/-α) ❌ = All 4 alpha genes missing (i.e. (--/--)
Alpha Thalassaemia Trait is the most severe form of the condition and patients rarely survive past infancy.
HbH disease causes strange 3 beta 1 alpha tetramers to form which can't carry oxygen, thus causing severe anaemia.
The skin of HbH Disease patient may be slightly discoloured as this condition is known to cause a mild
Extramedullary haematopoiesis in HbH Disease causes the pathological enlargement of which organ? The
Hb Barts Hydrops Fetalis is a condition whereby HbA cannot be produced due to the inability to synthesize alpha chains. This condition is typically incompatible with life.
Alpha Beta( Alpha, Beta ) Thalassaemia is considered to be more dangerous that Beta Alpha( Beta, Alpha ) Thalassaemia as the former affects HbA, HbA2 & HbF whereas the latter only affects HbA
β+/β or β0/β = Beta Thalassaemia β+/β+ or β0/β+ = Beta Thalassaemia β0/β0 = Beta Thalassaemia
Beta Thalassaemia Trait = ❌ Beta Thalassaemia Intermedia = ❌ Beta Thalassaemia Major = ❌
Beta thalassaemia major present around 6-24 months of age as the individual's HbF HbA HbA2( HbF, HbA, HbA2 ) falls
Children with beta thalassaemia major will typically present with which two key clinical signs?
Pallor
Failure to thrive
Reduced consciousness
Reduced appetite
Loss of accommodation reflex
Beta thalassaemia major can be separated from Alpha thalassaemia by looking at the child's blood - there will be an abundance of HbF in young beta thalassaemia patients.
Regular transfusion of patients with beta thalassaemia major aims to keep the Hb level at around 95-105 105-15 115-125( 95-105, 105-15, 115-125 )g/L
The main cause of mortality in beta thalassaemia major patients who are well treated is overload from the regular blood transfusions
Beta thalassaemia major patient with iron overload are typically treated via venesection
Sickle cell disease is caused by a mutation in codon 6 of the globin gene that substitutes glutamine to value producing Beta Globin S
When you have one normal (B) and one abnormal (BS) gene this is known as sickle . This is asymptomatic and makes you a carrier of sickle cell disease (not affected by the condition).
Sickle cell anaemia follows which kind of inheritance pattern? Autosomal .
Sickle Cell Anaemia causes Hyposplenism Hypersplenism( Hyposplenism, Hypersplenism ) due to repeated splenic infarcts
A patient with known HbSS is out with friends hiking. He progressively develops chest pain, shortness of breath, headache and skin pallor. He is likely experiencing a
Sickle cells can become stuck in arteries leading to sickle vaso-occlusion. This can cause a patient extreme pain dizziness itchiness nausea( pain, dizziness, itchiness, nausea )
Which of the following are common causes of sickle crises in HbSS patients?
Hypoxia
Dehydration
Infection
Stress
Cold Exposure
A Sickle Crisis should be managed by providing analgesia (if pain present, which it likely will be), hydration, oxygen and rest.
Long term management of Sickle Cell Disease includes: - Folic Acid (Vitamin B9) Vitamin B12 Vitamin A( Folic Acid (Vitamin B9), Vitamin B12, Vitamin A ) supplementation to increase RBC turnover - Hydroxycarbamide to induce produce of HbF HbA HbA2( HbF, HbA, HbA2 )
Due to the risk of occlusion, sickle cell anaemia patients are at a significantly higher risk of experiencing a stroke.
Raised HbA2 is diagnostic of which type of Thalassaemia? Beta Thalassaemia Trait Alpha Thalassaemia Trait HbH Disease Barts Hydrops Fetalis( Beta Thalassaemia Trait, Alpha Thalassaemia Trait, HbH Disease, Barts Hydrops Fetalis )
HPLC blood testing is normal in alpha beta( alpha, beta ) thalassaemia trait and thus DNA testing is necessary to confirm the condition.
