We report four unrelated families with a mild β(+)-thalassemia (β(+)-thal) allele consisting of two sequence variants at the 3' end of IVS-II: IVS-II-839 (T>C) (HBB: c.316-12T>C) and IVS-II-844 (C>A) (HBB: c.316-7C>A). These sequence variants alter the conserved polypyrimidine tract of the consensus splice acceptor sequence (Y11NYAG/G), which could reduce splicing efficiency. This may represent a common, yet under-diagnosed β(+)-thal allele in African populations.
We report the case of a father and daughter who are heterozygous for a duplication of 65 bp within exon 2 of the β-globin gene, resulting in an altered and truncated β-globin chain that is predicted to be non functional. The β-globin gene mutation is in cis with the common Hb A2 ' missense mutation of the δ-globin gene (HBD: c.49G>C), resulting in β-thalassemia (β-thal) trait with normal levels of Hb A2. This is the second report of this β(0)-thal mutation, and both families were associated with the Hb A2 ' variant and normal levels of Hb A2. Laboratories should be aware of the rare occurrence of β-thal trait with normal levels of Hb A2.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.