title: Misdiagnosis of a beta-thalassemia heterozygote using a reverse dot-blot method may be caused by a polymorphic locus in the wild type sequence of the beta-globin gene.
abstract: Reverse dot-blot is an effective method for detecting beta-thalassemia (beta-thal) mutations. In this study, we report the cause of a misdiagnosis by reverse dot-blot. One patient with a beta-globin genotype that was initially diagnosed as a codon 17 (A>T) homozygote by reverse dot-blot at our Clinic, was later shown to be a codon 17 (A>T) heterozygote by direct sequencing of the amplified fragment and by sequence analysis of a recombinant T vector plasmid containing an amplified fragment of the beta-globin gene. A polymorphic locus around the mutation site within the haploid DNA that lacked the codon 17 mutation was identified. This result suggests that when reverse dot-blot is used for the genetic diagnosis of beta-globin, polymorphic loci around the mutation site should be taken into consideration, and more allele specific oligonucleotide probes should be designed according to the polymorphic loci.
authors.affiliation: Department of Obstetrics and Gynecology, Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Yi
authors.forename: Jianxin
authors.initials: J
authors.lastname: Guo
authors.forename: Zhuqin
authors.initials: Z
authors.lastname: Chen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Lili
authors.initials: L
authors.lastname: Yu
authors.forename: Haichang
authors.initials: H
authors.lastname: Xie
authors.forename: Yaohua
authors.initials: Y
authors.lastname: Yan
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhong
authors.forename: Li
authors.initials: L
authors.lastname: Li
mesh_terms: D001483:Base Sequence; D002675:Child, Preschool; D003062:Codon / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods; D017931:DNA Primers; D006579:Heterozygote; D006801:Humans; D015151:Immunoblotting / Q000379:methods*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods*; D011110:Polymorphism, Genetic; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000235:genetics
chemical_list: D003062:Codon; D017931:DNA Primers; D055544:beta-Globins