Hb Mizuho (HBB: c.206T>C): Pitfalls of Screening Tests in an Unstable Hemoglobin Variant Diagnosed after Targeted Next-Generation Sequencing

Abstract

Hyperunstable hemoglobins (Hbs) are challenging to diagnose and may be missed on conventional hemolytic anemia work-up. Here, we report the case of a 2-year-old Indian boy with infancy-onset severe hemolytic anemia. Its etiology was revealed by targeted next-generation sequencing (NGS) to be the rare Hb Mizuho (HBB: c.206T>C). This variant had been missed on the initial routine laboratory investigations (heat and isopropanol tests for unstable Hbs) owing to its hyperunstable nature.

Keywords:

• Anemia
• heat instability test
• isopropanol instability test
• next-generation sequencing (NGS)
• unstable hemoglobin (Hb)

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

The NGS study was funded by the Department of Biotechnology, Ministry of Science and Technology, Government of India [grant no. BT/PR26461/MED/12/821/2018].