What are the haemoglobin disorders?

  • Commonest recessively inherited disorders of childhood in the UK
  • Potentially life-threatening conditions causing anaemia and other problems
  • Due to inheritance of variants in the genes for haemoglobin that alter the structure (e.g. haemoglobin S) or amount (e.g. beta thalassaemia) of haemoglobin
  • Not all combinations of haemoglobin gene variants cause a clinical disorder
  • Increased population mixing have led to these conditions being found in most populations

Sickle cell diseases: key points

What are they?

  • Blood disorders which affect the structure of haemoglobin

Frequency (England)

  • Affect 350 pregnancies annually
  • Estimated 12,500 people living with sickle cell diseases
  • Estimated 310,000 carriers (AS and AC)

Who do they affect?

  • Can affect anyone from any population
  • More common in people of African, Caribbean, Middle Eastern, Mediterranean and South Asian (Indian subcontinent) ancestry
  • Carriers are usually healthy

How are individuals affected?

  • Red blood cells "sickle" when they are short of oxygen, causing anaemia, risk of life-threatening infections, unpredictable attacks of severe pain ('crises'), morbidity (e.g. stroke), mortality

How are they managed?

  • Information for family on risk factors - dehydration, heat, cold, infection, stress
  • Prophylactic antibiotics from early age
  • Regular clinic attendance
  • Rapid access to medical help in emergency

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Beta and alpha thalassaemia: key points

What are they?

  • Blood disorders which cause early profound anaemia
  • Two types: beta (ß) thalassaemia major is commoner than alpha (a) thalassaemia major

Frequency (England)

  • Affect about 75 pregnancies per year
  • About 25 babies with beta thalassaemia major born annually
  • About 5 pregnancies affected with alpha thalassaemia major annually
  • Approximately 860 people living with major thalassaemia
  • Estimated 327,000 carriers

Who does thalassaemia affect?

  • Can affect anyone
  • Most common in people of Mediterranean , Middle Eastern, Asian (Indian subcontinent) or South East Asian ancestry
  • Carriers are usually healthy

How are individuals affected?

  • Red blood cells contain little haemoglobin, causing profound anaemia
  • Beta thalassaemia major: severe anaemia requiring regular blood transfusions from about 9 months of age
  • Alpha thalassaemia major: severe anaemia in the fetus during pregnancy leads to perinatal death (hydrops fetalis). Alpha thalassaemia intermedia: (haemoglobin H disease) causes moderate anaemia with little pathology in most cases

How is ß thalassaemia major managed?

  • Monthly blood transfusions, and iron chelation therapy to remove excess iron (introduced in transfused blood)
  • Bone marrow transplant is feasible in 25-30% of cases

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