| Abstrakt: |
β-Thalassemia (β-thal) is caused by mutations on the β-globin genes, causing reduced (β+) or absent (β0) 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 (HBB: c.151A>T) mutation and a Hb G-Siriraj (HBB: c.22G>A) mutation] by gene sequencing. However, his electrophoresis pattern was unusual: 90.8% Hb G-Siriraj, 5.9% Hb A2, 3.3% Hb F, no Hb A, no Hb Zürich-Langstrasse. His mother carried a β-thal trait (βA/βIVS-II-654) having mild anemia, with a classical electrophoresis pattern (95.1% Hb A, 4.4% Hb A2, 0.5% Hb F). His father was heterozygous for Hb G-Siriraj (βA/βG-Siriraj) but asymptomatic, with a corresponding electrophoresis pattern (63.9% Hb A, 3.5% Hb A2, 32.6% Hb G-Siriraj). In view of the family study results, the Hb Zürich-Langstrasse mutation in the proband was considered a de novo mutation occurring on the βIVS-II-654 allele that he inherited from his mother, resulting in a βIVS-II-654/Hb Zürich-Langstrasse genotype, which should be interpreted as a novel β0 mutation. This report illustrates that mutations in cis 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. [ABSTRACT FROM AUTHOR] |
