A Triple-Heterozygous β-Thalassemia Patient Demonstrated an Unusual Electrophoresis Pattern Due to a Novel β 0 Mutation [an IVS-II-654 (C>T) mutation with a Hb Zürich-Langstrasse ( HBB : c.151A>T) mutation in cis ]

• Published in: Hemoglobin 2022-05, p.1
• Main Authors: Liao, Juan, Li, Qin, Ling, Li-Qin, Liu, Chao-Nan, Huang, Xun-Bei, Zhou, Jing
• Format: Article
• Language: English
• ISSN: 1532-432X

β-Thalassemia (β-thal) is caused by mutations on the β-globin genes, causing reduced (β ) or absent (β ) synthesis of the β chains of hemoglobin (Hb). In this report, a 28-year-old male patient with anemia and jaundice, was diagnosed with triple-heterozygous β-thal [an IVS-II-654 (C>T) mutation, a Hb Zürich-Langstrasse ( : c.151A>T) mutation and a Hb G-Siriraj ( : c.22G>A) mutation] by gene sequencing. However, his electrophoresis pattern was unusual: 90.8% Hb G-Siriraj, 5.9% Hb A , 3.3% Hb F, no Hb A, no Hb Zürich-Langstrasse. His mother carried a β-thal trait (β /β ) having mild anemia, with a classical electrophoresis pattern (95.1% Hb A, 4.4% Hb A , 0.5% Hb F). His father was heterozygous for Hb G-Siriraj (β /β ) but asymptomatic, with a corresponding electrophoresis pattern (63.9% Hb A, 3.5% Hb A , 32.6% Hb G-Siriraj). In view of the family study results, the Hb Zürich-Langstrasse mutation in the proband was considered a mutation occurring on the β allele that he inherited from his mother, resulting in a β genotype, which should be interpreted as a novel β mutation. This report illustrates that mutations can confound genotype-phenotype correlations, therefore, just as DNA testing and Hb analysis, family study is also indispensable to the accurate identification of β-thal mutations.