Hb MOLFETTA [β126(H4)Val→Leu, GTG→CTG]: A NEW, SILENT, NEUTRAL β CHAIN VARIANT FOUND IN AN ITALIAN WOMAN

Abstract

We have identified a new neutral hemoglobin variant in a pregnant Italian woman, that resulted from a GTG → CTG replacement at codon 126 of the β chain, corresponding to a Val → Leu amino acid change at position β126(H4). Thermal and isopropanol stability tests were normal and there were no abnormal clinical features. Routine electrophoretic and ion exchange chromatographic methods for hemoglobin separation failed to show this variant, but reversed phase high performance liquid chromatography revealed an abnormal peak eluting near the normal β chain. No abnormal tryptic peptide was revealed on the high performance liquid chromatographic elution pattern of the total globin digest. The mutation was determined at the DNA level by amplification of the three β exons by polymerase chain reaction and direct sequencing of one exon that showed an abnormal migration on single strand conformational polymorphism analysis.