Homozygous mild beta-thalassaemia promoter transversion -71 C>T HBB:c.-121 C>T

Suha Mustafa Hassan, Abdulhakim Alrawas, Laila Al Khanbashi, Yasser Wali

Research output: Contribution to journalArticlepeer-review


Beta-thalassaemia is one of the most common genetic disorders worldwide, which is caused by absent or decreased synthesis of beta-globin chain subunits. Beta-thalassaemias are diverse groups of disease with a wide spectrum of clinical phenotypes. The clinical phenotypes can include asymptomatic forms of beta-thalassaemia minor, intermediate and severe transfusion dependent beta-thalassaemia major. Clinical severity varies depending on the underlying β globin gene mutation. There are a number of mild β-thalassaemia gene defects that could be referred as a € silent carrier'. Identifying the underlying molecular defect is essential to predict phenotype severity for optimal management, tailored treatment and improved quality of life. We report the first identification of a homozygous point mutation located within the promoter region of the β-globin gene at position -71 (C>T). The patient was a female child, who was referred to our clinic after she was found to have hypochromic microcytic anaemia with low haemoglobin (Hb) (67 g/L) and an Hb A 2 level at the upper limit of the normal value (3.7%). This observation is a new example of homozygous mild β-thalassaemia with a borderline Hb A 2 level, and illustrates a potential source of pitfall in the diagnosis of β-thalassaemia disease.

Original languageEnglish
Article numbere254416
JournalBMJ Case Reports
Issue number4
Publication statusPublished - Apr 1 2023


  • Genetics
  • Haematology (incl blood transfusion)
  • Paediatrics
  • Humans
  • beta-Thalassemia/genetics
  • Quality of Life
  • Female
  • Thalassemia
  • Promoter Regions, Genetic/genetics
  • beta-Globins/genetics

ASJC Scopus subject areas

  • General Medicine

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