title: The β-globin promoter -71 C>T mutation is a β+ thalassemic allele.
abstract: 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.
authors.affiliation: Sultan Qaboos University Hospital, Muscat, Oman.
authors.forename: Shoaib
authors.initials: S
authors.lastname: Al Zadjali
authors.forename: Yasser
authors.initials: Y
authors.lastname: Wali
authors.forename: Fatma
authors.initials: F
authors.lastname: Al Lawatiya
authors.forename: David
authors.initials: D
authors.lastname: Gravell
authors.forename: Salam
authors.initials: S
authors.lastname: Alkindi
authors.forename: Kareema
authors.initials: K
authors.lastname: Al Falahi
authors.forename: Rajagopal
authors.initials: R
authors.lastname: Krishnamoorthy
authors.forename: Shahina
authors.initials: S
authors.lastname: Daar
mesh_terms: D000483:Alleles; D001483:Base Sequence; D017931:DNA Primers; D006801:Humans; D009154:Mutation; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000235:genetics*
chemical_list: D017931:DNA Primers; D055544:beta-Globins