More than 1000 hemoglobin (Hb) variants have been identified. Hb Kirksey, a rare Hb variant involving mutation at codon 94 of α2-globin, is associated with low oxygen affinity. To our knowledge, there is no case report on Hb Kirksey in the literature, and, accordingly, the clinical features of patients with Hb Kirksey are currently unknown. We report here the case of a neonate who presented with asymptomatic low oxygen saturation on pulse oximetry (SpO2 ) just after birth, together with clinical analysis of the sister and cousin. Based on the presentations, Hb Kirksey does not seem to be associated with clinical abnormalities. Discrepancy between SpO2 and partial pressure of arterial oxygen (PaO2 ) detected on arterial blood gas analysis provided a clue to the diagnosis. Hb variants should be suspected and arterial blood gases should be measured in pediatric cases of unexplained low SpO2 .
Keywords: blood gas analysis; hemoglobin Kirksey; hemoglobinopathy; newborn; pulse oximetry.
© 2015 Japan Pediatric Society.