Mild thalassemia intermedia resulting from a new insertion/frameshift mutation in the beta-globin gene

Hematological investigation of an antenatal patient led to the identification of a new beta-thalassemia mutation involving the net insertion of eight nucleotides into exon 2 of the beta-globin gene. As a result of the shift in the protein reading frame, this gene codes for an elongated beta-globin chain (159 amino acids) with an abnormal amino acid sequence beyond residue beta 99. There is no evidence of any abnormal hemoglobin in the circulation. The patient has a mild form of beta-thalassemia intermedia with moderate anemia, evidence of iron overload, severe red cell morphological changes, a significant reticulocytosis, and a marked increase in the proportion of fetal hemoglobin.