Sickle cell disease due to compound heterozygosity for Hb S and a novel 7.7‐kb β‐globin gene deletion

• Published in: European journal of haematology Vol. 78; no. 1; pp. 82 - 85
• Main Authors: Andersson, B. Anders R., Wering, Mikaela E. L., Luo, Hong‐Yuan, Basran, Raveen K., Steinberg, Martin H., Smith, Hedy P., Chui, David H. K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-01-2007
• Subjects: Adult; Anemia, Sickle Cell - complications; Anemia, Sickle Cell - diagnosis; Anemia, Sickle Cell - genetics; Base Sequence; Female; Gene Deletion; Globins - genetics; Hemoglobin, Sickle - genetics; Heterozygote; Humans; molecular diagnostics; Molecular Sequence Data; Reverse Transcriptase Polymerase Chain Reaction; sickle cell anemia; β‐globin gene deletion; β‐thalassemia
• ISSN: 0902-4441; 1600-0609
• DOI: 10.1111/j.1600-0609.2006.00771.x

A young woman originally from Cape Verde islands presented with mild sickle cell disease. Her blood counts and hemoglobin analysis results initially suggested that she might be either homozygous for the sickle cell hemoglobin (Hb S) with concomitant α‐thalassemia, or compound heterozygous for Hb S and β0‐thalassemia, deletional δβ‐thalassemia or hereditary persistence of fetal hemoglobin (HPFH). We utilized a novel polymerase chain reaction (PCR)‐based screening technique and found a hitherto unrecognized 7.7‐kb deletion, starting from the HBB IVSII to 3′ downstream of the β‐globin gene. This diagnostic approach can be applied to decipher other similar deletional mutations. This is the second known deletion that removes the 3′‐end but preserves the integrity of the 5′‐end of the β‐globin gene. Furthermore, the identification of the deletion allows proper genetic counseling for affected families.