Beta thalassemia forms are classified using two systems: genotypic and phenotypic. The genotypic system classifies beta thalassemias based on their zygosity (heterozygous vs. homozygous) and the degree of the mutation (partial vs. full). This classification system has six forms of beta-thalassemia. In the phenotypic system, there are four forms of beta-thalassemia based on the degree of clinical symptoms experienced by the patient.
Key: + = partial deletion or inactivation of gene loci, 0 = full deletion or inactivation of gene loci
Genotypic System:
- B0/B0
- B0/B+
- B+/B+
- B0/B
- B+/B
- Bsc/B
Phenotypic System:
- Beta thalassemia major
- Beta thalassemia intermedia
- Beta thalassemia minor
- Beta thalassemia minima
