Epidemiology

It is the commonest genetic disorder in the world

• although a globin variant is seen in around 5% of the population, only 1.7 % has alpha or beta thalassemia trait (1)
• according to estimations from cohort studies, there are 1.5% (80-90 million people) carriers of β thalassaemia and 5% carriers of α thalassaemia world wide (2)
• men and women are equally affaected
• seen in approximately 4.4 of every 10,000 live births (1)

214,000 people in the UK carry the beta-thalassaemia gene

• it occurs in a very high frequency in a tropical belt extending from Africa, throughout the Mediterranean region, the Middle East, the Indian subcontinent, and throughout South West Asia
• they occur sporadically in every population
• it is possible that the heterozygote state provides protection against malaria, thus explaining its high carrier rate in certain populations

Reference:

• (1) Muncie HL Jr, Campbell J. Alpha and beta thalassemia. Am Fam Physician. 2009;80(4):339-44.
• (2) Peters  M, et al. Diagnosis and management of thalassaemia. BMJ 2012; 344