“The Long Journey of Unexplained Erythrocytosis”: Erythrocytosis due to High-Oxygen Affinity Hemoglobinopathy – Hemoglobin Variant Little Rock (HBB: c.432C>A) – A Report of a Swiss Family and Review of the Literature

Abstract

The differential diagnosis of erythrocytosis is complex, involving a tailored algorithm. Congenital causes are rare and such patients commonly face a long journey looking for diagnosis. This diagnosis requires expertise and accessibility to modern diagnostic tools. We present the case of a young Swiss man with long-standing erythrocytosis of unknown origin and his family. The patient had an episode of malaise as he went skiing above 2,000m altitude. In the blood gas analysis, the p50 was low (16 mmHg) and erythropoietin was normal. Using Next Generation Sequencing (NGS) a mutation in the Hemoglobin subunit beta gene was found, a pathogenic variant known as Hemoglobin Little Rock causing high oxygen affinity. Some family members also had unexplained erythrocytosis, therefore the mutational status of the family was analyzed, the grandmother and mother showed the presence of the same mutation. The use of modern technology offered finally a diagnosis to this family.

Rare coinheritance of hemoglobin vancleave with severe beta-thalassemia mutation in a patient with secondary erythrocytosis

“…Differential diagnosis of high oxygen affinity may be laborious and complex due to its plethora of clinical presentations and its unknown prevalence in the population 5 , 16 . Particularly in Malaysia, where hemoglobin disorders are highly prevalent, patients with erythrocytosis should be prioritized for hemoglobin anomaly investigations via direct DNA sequencing.…”