Hypoxemia as the only manifestation of structural hemoglobinopathy

Structural hemoglobinopathies are the result of gene mutations that cause alterations in the molecular structure of hemoglobin. They have a very variable clinical expression: from minimally symptomatic to severe pathology. We present the case of a 3-year-old boy admitted for atypical pneumonia with hypoxemia who, after 11 days of admission, maintained peripheral oxygen saturations (SpO₂) of 92-94% without other symptoms, physical examination and normal cardiopulmonary study. In outpatient follow-up, peripheral desaturation persists with gasometry and normal arterial co-oxymetry. Patient's father with the same findings in pulse oximetry as in arterial blood gases. When a structural hemoglobinopathy was suspected, a genetic and electrophoretic study was performed, detecting the presence of hemoglobin Arta.