# Microcytosis Merits Evaluation: A Case Report of Hemoglobin S With Hereditary Persistence of Fetal Hemoglobin (HbS-HPFH Syndrome)

## TL;DR

A case report shows that microcytosis can lead to a rare hemoglobin disorder diagnosis, which in turn explains unrelated symptoms like chronic hip pain.

## Contribution

Highlights the importance of evaluating microcytosis to uncover rare hemoglobinopathies like HbS-HPFH syndrome.

## Key findings

- Microcytosis in a 34-year-old male led to a diagnosis of HbS-HPFH syndrome.
- The diagnosis explained the patient's chronic hip pain and bilateral osteonecrosis of the femurs.
- Microcytosis should not be ignored and requires a targeted evaluation in primary care.

## Abstract

Microcytosis is commonly encountered in primary care. Among patients with normal iron stores or compatible family history, hemoglobin electrophoresis, traditionally performed with gel electrophoresis and now through combination capillary electrophoresis/high-performance liquid chromatography, can diagnose thalassemic disorders or, rarely, a hemoglobinopathy. We present a case of an incidentally discovered microcytosis in a 34-year-old male patient where the workup led to a diagnosis of Hemoglobin S with Hereditary Persistence of Fetal Hemoglobin (HbS-HPFH syndrome). The diagnosis led providers to re-evaluate the patient’s chronic hip pain, upon which the patient was found to have bilateral osteonecrosis of the femurs.

Microcytosis is a lab abnormality that is often asymptomatic and, therefore, may be ignored or overlooked. When encountering microcytosis in primary care, it is important to identify the etiology using a brief, targeted approach. This may directly impact management and can prove helpful when considering future complaints of the patient.