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

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.