Hemoglobin S/OARAB: Thirteen new cases and review of the literature

✍ Scribed by Zimmerman, Sherri A.; O'Branski, Erin E.; Rosse, Wendell F.; Ware, Russell E.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 354 KB
• Volume: 60
• Category: Article
• ISSN: 0361-8609
• DOI: 10.1002/(sici)1096-8652(199904)60:4<279::aid-ajh5>3.0.co;2-2

✦ Synopsis

Hemoglobin S/O Arab (Hb S/O Arab ) is a rare compound heterozygous hemoglobinopathy characterized by the presence of two variant ␤-globin chains: ␤ 6 Glu → Val (Hb S) and ␤ 121 Glu → Lys (Hb O Arab ). The diagnosis of Hb S/O Arab requires electrophoresis on both cellulose acetate and citrate agar, since Hb O Arab co-migrates with Hb C at alkaline pH and close to Hb S at acidic pH. To date only case reports and small series of patients with Hb S/O Arab have been described. To better characterize the clinical and laboratory aspects of this unusual disorder, we reviewed the Duke University Medical Center experience. We identified 13 African-American children and adults with Hb S/O Arab ranging in age from 2.7 to 62.5 years. All patients had hemolytic anemia with a median Hb of 8.7 gm/dL (range 6.1-9.9 gm/dL), and a median reticulocyte count of 5.8% (range 1.2-10.3%). The peripheral blood smear typically showed sickled erythrocytes, target cells, polychromasia, and nucleated red blood cells. All 13 patients have had significant clinical sickling events including acute chest syndrome (11), recurrent vasoocclusive painful events (10), dactylitis (7), gallstones (5), nephropathy (4), aplastic crises (2), avascular necrosis (2), leg ulcers (2), cerebrovascular accident (CVA) (1), osteomyelitis (1), and retinopathy (1). Four patients have died, including two from pneumococcal sepsis/meningitis at ages 5 and 10 years, one of acute chest syndrome at age 14 years, and one of multiorgan failure at age 35 years. We conclude that Hb S/O Arab disease is a severe sickling hemoglobinopathy with laboratory and clinical manifestations similar to those of homozygous sickle cell anemia. Am.