title: Haplotypes linked to three rare beta-thalassemia mutations, originally reported in Tunisia.
abstract: The polymorphism of the beta-globin gene haplotypes and frameworks are useful in the determination of the unicentric and multicentric origin of a mutational event. In order to improve our knowledge of the chromosomal background of the beta-globin gene in three beta-thalassemia (thal) mutations originally reported in Tunisia, namely codons 25/26 (+T), codon 30 (G-->C) and IVS-I-2 (T-->G), we have investigated 13 unrelated individuals. There were five non transfusion-dependent patients homozygous for the IVS-I-2 (T-->G) mutation, five others were homozygous for the codon 30 (G-->C) mutation, one was a homozygote for the codons 25/26 (+T) insertion mutation and one patient was a compound heterozygote for the codon 39 (C-->T) and codon 25/26 (+T) mutations; the last patient had a betaS/codon 25/26 (+T) compound heterozygous genotype. Haplotype analysis was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based methods. The framework polymorphism was established by direct sequencing. beta-Globin gene analyses demonstrated that all IVS-I-2 (T-->G) cases were associated with haplotype IX; the codon 30 (G-->C) mutation was supported by haplotype I, while the codons 25/26 (+T) mutation was linked to haplotypes I and IX.
authors.affiliation: Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital d'Enfants, Tunisie.
authors.forename: Amina
authors.initials: A
authors.lastname: Bibi
authors.forename: Taieb
authors.initials: T
authors.lastname: Messaoud
authors.forename: Slaheddine
authors.initials: S
authors.lastname: Fattoum
mesh_terms: D003062:Codon / Q000235:genetics; D004252:DNA Mutational Analysis; D005006:Ethnicity / Q000235:genetics; D005260:Female; D005914:Globins / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics*; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D016254:Mutagenesis, Insertional; D009154:Mutation; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012805:Sickle Cell Trait / Q000150:complications / Q000235:genetics; D014416:Tunisia; D017086:beta-Thalassemia / Q000150:complications / Q000235:genetics*
chemical_list: D003062:Codon; D005914:Globins