title: Incidence of haemoglobinopathies in various populations - the impact of immigration.
abstract: OBJECTIVE
  The aim of this study was to update the incidence data of beta thalassaemia mutations in various populations and compare it to the spectrum of mutations in the United Kingdom (UK) population in order to determine the impact of immigration.
  
  
  METHODS
  Published data for the beta-thalassaemia mutation spectrum and allele frequencies for 60 other countries was updated and collated into regional tables. The beta-thalassaemia mutations in the UK population have been characterised in 1712 unrelated carriers referred for antenatal screening. Similarly, the alpha-thalassaemia mutations in the UK population have been characterised in 2500 possible alpha-thalassaemia carriers.
  
  
  RESULTS
  A total of 68 different beta-thalassaemia mutations were identified in couples requiring screening for antenatal diagnosis in the UK population. Of these mutations, 59 were found in immigrants to the UK, from all major ethnic groups with a high incidence of haemoglobinopathies. A total of 40 different alpha-thalassaemia mutations were characterised in the UK population. Ten deletion mutations were identified, including all the Southeast Asian and Mediterranean alpha(0)-thalassaemia mutations. In addition, 30 non-deletion alpha(+)-thalassaemia mutations were discovered, accounting for 46% of the worldwide known non-deletion mutations.
  
  
  CONCLUSIONS
  The impact of immigration has resulted in the UK population having a higher number of beta-thalassaemia mutations and alpha-thalassaemia mutations than any of the 60 other countries with a published spectrum of mutations, including both endemic countries and the non-endemic countries of Northern Europe. The racial heterogeneity of the immigrant population in a non-endemic country significantly increases the spectrum of haemoglobinopathy mutations and their combinations found in individuals, making the provision of a molecular diagnostic prenatal diagnosis service more challenging.
authors.affiliation: National Haemoglobinopathy Reference Laboratory, Oxford Radcliffe Hospitals NHS Trust, Oxford, England, UK.
authors.forename: Shirley
authors.initials: S
authors.lastname: Henderson
authors.forename: Adele
authors.initials: A
authors.lastname: Timbs
authors.forename: Janice
authors.initials: J
authors.lastname: McCarthy
authors.forename: Alice
authors.initials: A
authors.lastname: Gallienne
authors.forename: Margaretha
authors.initials: M
authors.lastname: Van Mourik
authors.forename: Gillian
authors.initials: G
authors.lastname: Masters
authors.forename: Alison
authors.initials: A
authors.lastname: May
authors.forename: Mohamed S M
authors.initials: MS
authors.lastname: Khalil
authors.forename: Anna
authors.initials: A
authors.lastname: Schuh
authors.forename: John
authors.initials: J
authors.lastname: Old
mesh_terms: D017954:Africa South of the Sahara / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D004641:Emigration and Immigration / Q000706:statistics & numerical data*; D005060:Europe / Q000453:epidemiology; D006453:Hemoglobinopathies / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D019083:Mediterranean Region / Q000453:epidemiology; D008877:Middle East / Q000453:epidemiology; D009154:Mutation; D044382:Population Groups / Q000706:statistics & numerical data*; D017086:beta-Thalassemia / Q000453:epidemiology / Q000235:genetics