Clinical case of hereditary hemoglobinopathy in a child

Pulse oximetry has been used in medicine since the 1980s. Currently, it is widespread in all areas of medicine. There are many cases when low pulse oximetry readings are the consequence of impaired ability of the respiratory organs to oxygenate venous blood flowing to the lungs. On the other hand, low pulse oximetry readings can be associated with hemoglobinopathies that alter the binding properties and absorption spectrum of hemoglobin. The article describes a clinical case of a 13-year-old patient. During a routine examination regarding the course of an acute respiratory viral infection during the SARS-CoV-2 pandemic, asymptomatic low oxygen saturation was detected when measured with a pulse oximeter. The boy underwent extensive testing to look for cardiac or pulmonary causes of desaturation. During the examination, a discrepancy was found between pulse oximetry readings and partial pressure of oxygen with arterial blood saturation, which suggested that the patient had hemoglobinopathy. Considering the possible hereditary nature of hemoglobinopathy, pulse oximetry was performed on the patient’s parents. Mother had asymptomatic desaturation. Hemoglobin electrophoresis revealed an abnormal structural variant. Subsequent DNA analysis revealed a 1-nucleotide substitution in exon 2 of the HbA2 gene, which led to the substitution of histidine for aspartame. This genetic variant has not previously been described in the Human Polymorphism Database. Thuswise, the diagnosis of hereditary hemoglobinopathy was confirmed.