Hb Mizuho Case Report; Early Genomic Testing Facilitates a Life Changing Diagnosis

Abstract

Unstable variant hemoglobinopathies are an uncommon cause of hemolysis in the pediatric patient and may cause a delay in diagnosis if there is not a high index of suspicion. Hemoglobin (Hb) Mizuho is a rare unstable hemoglobinopathy caused by a pathogenic variant of the HBB gene with a severe phenotype. Here we report on the first known case of Hb Mizuho in Australia, presenting with features of acute and chronic hemolysis. The morphological features on blood film review, in conjunction with biochemical findings and other clinical features, did not immediately suggest an alternative diagnosis and a Next Generation Sequencing gene analysis approach was taken to investigate genes associated with red blood cell disorders and atypical uremic syndrome. The HBB Mizuho variant was detected and established the diagnosis. This report highlights the challenge of diagnosing Hb Mizuho on conventional testing and the need for early genomic testing to clarify a diagnosis.

Keywords:

• Hemoglobin Mizuho
• unstable hemoglobinopathy
• hemolysis
• HBB gene variant

Acknowledgements

We would like to thank the patient and their family for their support in this case report.

Author contributions

Manuscript conceptualization, O.E. and H.T.; formal analysis, L.R., C.P., S.M., D.H. and K.S.; clinical data and interpretation, L.R., C.P. and H.T.; writing—original draft preparation, O.E., H.T., L.R., S.M. and CP.; figure preparation, O.E., L.R., S.M. and CP.; writing—review and editing, O.E. and H.T. All authors have read and agreed to the published version of the manuscript.

Financial interests

The authors have no relevant financial or non-financial interests to disclose.

Disclosure statement

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

Informed consent

Informed consent was obtained from legal guardians for the submission of the case report to the journal.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.