title: Normal Hb A2 β-thalassemia trait: frameshift mutation (HBB: c.187_251dup) in cis with the Hb A2' δ-globin gene missense mutation (HBD: c.49G>C).
abstract: 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.
authors: Hamilton Regional Laboratory Medicine Program, Hamilton Health Sciences, Hamilton, Ontario, Canada. waye@hhsc.ca
authors: John S
authors: JS
authors: Waye
authors: Barry
authors: B
authors: Eng
authors: Laurie
authors: L
authors: Hellens
authors: Betty-Ann
authors: BA
authors: Hohenadel
authors: Lisa M
authors: LM
authors: Nakamura
authors: Lynda
authors: L
authors: Walker
mesh_terms: D000328:Adult; D001483:Base Sequence; D004252:DNA Mutational Analysis; D005260:Female; D016368:Frameshift Mutation; D020440:Gene Duplication; D005838:Genotype; D006443:Hemoglobin A2 / Q000235:genetics*; D006801:Humans; D020125:Mutation, Missense; D012689:Sequence Homology, Nucleic Acid; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000175:diagnosis / Q000235:genetics*; D055546:delta-Globins / Q000235:genetics*
chemical_list: D055544:beta-Globins; D055546:delta-Globins; D006443:Hemoglobin A2