THE Hb S/β⁺-Thalassemia Phenotype Demonstrates that the IVS-I (−2) (A>C) Mutation is a Mild β-Thalassemia Allele

Abstract

We report a family in which two siblings are compound heterozygotes for Hb S [β6(A3)Glu→Val] and a rare β-globin mutation [IVS-I (−2) (A>C)]. Both patients had significant levels of Hb A, indicating that the IVS-I (−2) mutation is a relatively mild β⁺-thalassemia (β⁺-thal) allele. This mutation, in compound heterozygosity with Hb S, does not necessarily lead to a mild clinical course.

Keywords:

• Splice site mutation
• Mild hematological phenotype
• Hb S/β-thalassemia (β-thal)