Evidence for Three Distinct Classes of Phenotype Severity in Beta-Thalassaemia

Background: Classification of phenotype severity in patients with beta-thalassaemia has so far relied mainly on expert opinion using parameters of genotype, clinical features at diagnosis, and transfusion requirement. The aim of this study was to use a large dataset of patients with beta-thalassaemia and evaluate a classification system based on onset variables agreed on by an international expert group, including age at diagnosis, at first transfusion, and at first iron chelation. Methods: A retrospective dataset of 7910 patients with homozygous or compound heterozygous beta-thalassaemia was used and subjected to cluster and classification analysis starting with the onset variables. Result…