Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:13

710 High-Oxygen-Affinity Hemoglobins

High-Oxygen-Affinity Hemoglobins.......................

AKIKO SHIMAMURA, MD, PhD

history & physical

History

■Positive family history (autosomal dominant inheritance) though

may also occur sporadically

■Patients often asymptomatic

Signs & Symptoms

■Splenomegaly is uncommon

tests

Blood

■Polycythemia with erythrocytosis (hb ranges between 17–22 g/dl)

■No evidence of hemolysis

■Normal rbc morphology on peripheral smear

■Only 50% are detectable by hemoglobin electrophoresis

Specific Diagnostic Tests

■Low P50 and hemoglobin oxygen dissociation curve shifted to the

left (decreased oxygen availability)

■Sequence analysis of alpha or beta globin genes

differential diagnosis

■Polycythemia vera

■Mutations in the erythropoietin receptor

■Increased erythropoietin production

■Some unstable hemoglobins have abnormal oxygen dissociation

curves

management

■No treatment generally required

■Hyperviscosity-related symptoms are rare

■Generally no adverse effect on fetus of mother with high oxygen

affinity hemoglobin

specific therapy

n/a