A Hemoglobin Variant Causing an Unexplained Low Oxygen Saturation by Pulse Oximetry: Two Case Reports

Area of Science:

• Neonatal Medicine
• Genetics
• Hematology

Background:

• Pulse oximetry is a standard tool for neonatal resuscitation and congenital heart disease screening.
• Accurate oxygen saturation measurements are vital for neonatal care.
• Hemoglobin (Hb) variants are a potential cause of discrepancies in pulse oximetry readings.

Observation:

• Two unrelated newborns presented with low oxygen saturation detected by pulse oximetry.
• Genetic analysis identified a heterozygous mutation in the gamma-globin gene (HBG1) in exon 2 (c.202G>A, p.Val68Met) in both infants.
• This specific mutation results in a fetal Hb variant.

Findings:

• The identified gamma-globin gene mutation leads to a fetal hemoglobin variant.
• This Hb variant can interfere with standard pulse oximetry measurements.
• The presence of Hb variants should be considered in the differential diagnosis of neonatal hypoxemia.

Implications:

• Accurate interpretation of pulse oximetry in newborns requires consideration of potential Hb variants.
• Early genetic testing can aid in diagnosing the cause of unexpected low oxygen saturation.
• Understanding Hb variants improves diagnostic accuracy in neonatal critical care and screening programs.