title: Identification of a variation in the IVSII of α2 gene and its frequency in the population of Guangxi.
abstract: OBJECTIVE
  During thalassemia screening, a previously unidentified α2 gene variation in α-globin gene cluster was isolated. This variation was distinct from other variations known to confer thalassemia as assessed by conventional thalassemia genotype analysis. Because the sample in the thalassemia screening was positive (MCV=83.6fL, MCH=26.1pg/cell, Hb=11.3g/dL), further analysis was required.
  
  
  METHODS
  MLPA (multiplex ligation-dependent probe amplification) and sequencing were used for analysis, and a qPCR system was designed for the frequency study.
  
  
  RESULTS
  The MLPA result showed that there was a mutation or small fragment deletions between 34247 (160bp probe) and 34618 (196bp probe) in α-globin gene cluster (NG_000006.1). Through sequencing, this variation was identified as HBA2: c.301-24delGinsCTCGGCCC. The gene polymorphisms similar to HBA2:c.301-24delGinsCTCGGCCC are α121 and α212. Since α212 is unrelated to microcytosis, and the structure of HBA2: c.301-24delGinsCTCGGCCC is similar to α212, this change is more appropriately considered as a polymorphism. The allele frequency of HBA2: c.301-24delGinsCTCGGCCC is 0.184% in this region.
  
  
  CONCLUSIONS
  There is a certain ratio for HBA2:c.301-24delGinsCTCGGCCC carriers among the Chinese population. The HBA2:c.301-24delGinsCTCGGCCC variant results in an abnormal result from MLPA analysis. Investigators performing thalassemia screening in Guangxi region should be aware of the HBA2:c.301-24delGinsCTCGGCCC variant to avoid misinterpretation of the MLPA results.
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China.
authors.forename: Wanrong
authors.initials: W
authors.lastname: Pang
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China; Qinzhou Key Laboratory of Molecular and Cell Biology on Endemic Diseases, Qinzhou, Guangxi 535099, PR China.
authors.forename: Xunjin
authors.initials: X
authors.lastname: Weng
authors.affiliation: Qinzhou Key Laboratory of Molecular and Cell Biology on Endemic Diseases, Qinzhou, Guangxi 535099, PR China; The First People's Hospital of Qinzhou, Qinzhou, Guangxi 535099, PR China.
authors.forename: Xuehe
authors.initials: X
authors.lastname: Ye
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China; Qinzhou Key Laboratory of Molecular and Cell Biology on Endemic Diseases, Qinzhou, Guangxi 535099, PR China; Qinzhou University, Qinzhou, Guangxi 535099, PR China. Electronic address: lab@longju.net.
authors.forename: Ju
authors.initials: J
authors.lastname: Long
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China.
authors.forename: Suping
authors.initials: S
authors.lastname: Wu
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China; Qinzhou Key Laboratory of Molecular and Cell Biology on Endemic Diseases, Qinzhou, Guangxi 535099, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.affiliation: Qinbei Maternal and Child Health Care Hospital of Qinzhou, Qinzhou, Guangxi 535099, PR China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Wei
authors.affiliation: Institute of Agro-Products Processing and Nuclear-Agricultural Technology, Hubei Academy of Agricultural Sciences, Wuhan, Hubei 430064, PR China.
authors.forename: Mingli
authors.initials: M
authors.lastname: Chen
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Tang
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China.
authors.forename: Shengying
authors.initials: S
authors.lastname: Qiu
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Qinzhou, Guangxi 535099, PR China.
authors.forename: Chenghong
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D002681:China; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008969:Molecular Sequence Data; D060885:Multiplex Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011247:Pregnancy; D017384:Sequence Deletion; D013789:Thalassemia / Q000235:genetics*; D055542:alpha-Globins / Q000235:genetics*
chemical_list: D055542:alpha-Globins
keywords: MLPA; Thalassemia; α thalassemia; α2 polymorphism