Make the Diagnosis: Blue Skin Bewilderment

(MedPage Today) -- Case Findings: A pregnant woman presents for a routine antenatal workup. Her skin was described as lavender blue, and has always had this color. Her father has the same skin tone. A venous sample was dark brown (shown on the right, the left is a normal sample) for HB and electrophoresis, and her fingers/nail beds were cyanotic. Other initial findings: Oxygen saturation via pulse oximetery = 45% (low); arterial partial pressure of oxygen (PO2) = 98.3; oxygen saturation (SaO2)=80%; HB, G6PDH, and reticulocyte count was normal. What is your diagnosis?
Source: MedPage Today Hematology/Oncology - Category: Hematology Source Type: news