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The β‐globin promoter −71 C>T mutation is a β+ thalassemic allele
Author(s) -
Al Zadjali Shoaib,
Wali Yasser,
Al Lawatiya Fatma,
Gravell David,
AlKindi Salam,
Al Falahi Kareema,
Krishnamoorthy Rajagopal,
Daar Shahina
Publication year - 2011
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.2011.01687.x
Subject(s) - thalassemia , allele , genetics , mutation , compound heterozygosity , loss of heterozygosity , biology , globin , phenotype , microbiology and biotechnology , hemoglobinopathy , heterozygote advantage , gene , hemolytic anemia , immunology
A novel β‐globin gene promoter (−71 C>T) nucleotide change was recently posted to the HbVar database (ID 2701) without precision on phenotype and ethnicity. We found the same change in compound heterozygosity with Hb S [β6(A3)Glu>Val] in an Omani family with almost equal expression of Hb A and Hb S. This suggested that the −71 C to T mutation may be a mild β‐thalassemic allele. Subsequent search found three other independent cases with the same atypical Hb A:Hb S ratio, further confirming the mild thalassemic feature of this mutation. In addition, molecular screening of a set of subjects (with only Hb A) with borderline Hb A 2 or MCV values revealed the presence of −71 C>T change in heterozygous state, altogether assigning the mutation as a mild β + thalassemic allele. In a region such as Oman, where several genetic conditions of the red blood cell coexist (α‐ and β‐thalassemia, Hb S, Hb D, Hb E) in significant frequencies, it is crucial to decipher the molecular basis of these atypical forms of β + thalassemias, especially in a genetic counseling setting.