Ferranti P, Parlapiano A, Malorni A, Pucci P, Marino G, Cossu G, Manca L, Masala B. Hemoglobin Ozieri: a new alpha-chain variant (alpha 71(E20)Ala-->Val). Characterization using FAB- and electrospray-mass spectrometric techniques.
BIOCHIMICA ET BIOPHYSICA ACTA 1993;
1162:203-8. [PMID:
8448185 DOI:
10.1016/0167-4838(93)90148-k]
[Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A new silent hemoglobin variant, Hb Ozieri (alpha 71(E20)Ala-->Val), was observed in five apparently unrelated newborn babies during a screening for hemoglobinopathies on the island of Sardinia. This asymptomatic variant was detected by means of isoelectric focusing (IEF), isolated using IEF in an immobilized ultranarrow pH-gradient and characterized at the structural level using FAB- and electrospray-mass spectrometric techniques. A Val for Ala substitution was unambiguously detected at position 71 of the alpha-globin chain. This substitution indicates that a C to T transition occurred in the GCG codon for Ala which contains one of the 35 unmethylated CpG dinucleotides of the alpha-globin gene. This observation brings the number of variants due to a mutation in the alpha-globin gene CpGs (the third instance of a silent mutation) to 13 and raises the possibility that unmethylated CpGs might be hotspots for mutations as the methylated ones.
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