Curriculum · Hematology
Beta-thalassaemia major
What it is
Beta thalassemia major is the homozygous beta form, two mutated beta-globin genes, written as genotype b0/b0 or b0/b+. It is autosomal recessive, and prevalent in the tropical and subtropical regions, including the Middle East, parts of Africa, the Indian subcontinent and Southeast Asia.
How it presents
Initial presentation is at age 6-12 months, when HbA replaces HbF. What follows is:
- Severe anemia and jaundice
- Gross hepatosplenomegaly, from extramedullary hematopoiesis
- Radiologic changes from an expanded marrow cavity, and extramedullary hematopoietic masses, that is erythroid tissue tumours
- Skull x-ray with a hair-on-end appearance
- Pathologic fractures, which are common
- Evidence of increased Hb catabolism, for example pigmented gallstones
A worked case that reads close to this is set against a different answer: a 6-year-old girl seen for short status, with height and weight below the 10 percentile, pallor, frontal bossing, prominent maxillary eminencies and hepatosplenomegaly, Hb 7.0 g/dL, MCV 65, HbA 60%, HbA2 4% and HbF 36% - and the answer marked on it is beta thalassemia intermedia, not major. Earlier still, at 9 months, it can be no more than failure to thrive and poor feeding.