A 7-month-old infant was referred to our hematology clinic for workup for presumed polycythemia (Hgb 19gm/dl), detected by his pediatrician through routine blood work. He also had failure to thrive, with both his weight and height well below the fifth percentile, and had delayed fine and gross motor skills. His birth history was significant for prematurity at 35-weeks gestational age; he exhibited hyperbilirubinemia on day 3 of life, which required phototherapy for 48 hours, and hypoglycemia that required close monitoring. His hemoglobin at birth was 24.2 gm/dl. His parents were third-degree consanguineously related (first cousins) from Bangladesh.
Pertinent Laboratory Findings
Red blood cell count: 7.52 M/uL (Ref 3.8–5.4 M/uL)
Hemoglobin: 19.1 g/dl
Hematocrit: 67.9%
Normal arterial oxygen saturation (SaO2) and arterial oxygen tension (PaO2)