Clinical and biological specificity of beta-thalassemia intermedia: a case report

We report the case of a nine-year-old girl, of Moroccan origin, hospitalised for fever and stomach ache. The clinical and biological investigations showed merely a moderate enlargement of the spleen associated with discrete regenerative hemolytic anemia. The etiologic analysis of the hemolysis was completed by the electrophoresis of hemoglobin (Hb) that revealed total absence of HbA, with the presence of 98.7% of HbF and 1.3% of HbA2. These results led to a diagnosis of β0 thalassemia associated with an intermediate phenotype, i.e. beta thalassemia intermedia (BTI). The molecular study of the β-globin gene evidenced a homozygous mutation at codon 35 of the exon 2 TAC>TAA (HBB: c.108C>A) leading to the premature stop codon. The study of several polymorphisms involved in the regulation of the expression of HbF concords with the intermediate phenotype found in the patient. This observation offers an opportunity to redefine BTI and further explore its clinical and genetic specificity.