Two New α-Thalassemia Point Mutations that are Undetectable by Biochemical Techniques

Abstract

We report two new point mutations causing α-thalassemia (α-thal) that could not be characterized by conventional biochemical studies. The first mutation is a single base substitution at codon 123 of the α1-globin gene [α123(H6)Ala→Pro, GCC>CCC (α1)] and leads to the substitution of a proline residue in the H helix. The resulting unstable hemoglobin (Hb) variant has been named Hb Voreppe. The second is a frameshift of the α2 gene due to a deletion (−C), either of the third base of codon 112 or of the first base of codon 113, that causes a premature stop codon at position 132.

Keywords:

• α-Thalassemia (α-thal)
• Hemoglobin (Hb) variants
• Point mutations
• Frameshift