The diagnosis and molecular analysis of a novel 21.9kb deletion (Qinzhou type deletion) causing α+ thalassemia.
α-Thalassemia is a common single-gene genetic disease that can cause Hb Bart's hydrops fetalis and Hb H disease in tropical and subtropical regions. When examining conventional thalassemia genes, an only detected --(SEA) genotype sample needs further analysis. In doing so, we found a novel 21.9kb deletion (Qinzhou type deletion). The deletion position of the novel 21.9kb deletion is from 14373bp to 36299bp of the α-globin gene cluster (NG_000006.1); thus, there exists a 21927bp sequence deletion, into which a 29bp sequence is added. After sequence analysis, a group of Gap-PCR primers were synthesized to diagnose this novel thalassemia genotype. Through pedigree analysis, we deduced that the propositus obtained the novel alleles from her mother. The genotype of this propositus is --(SEA)/-α(21.9) and its phenotype conforms to the characteristics of Hb H disease, establishing that the combination between -α(21.9) genotype and α(0) genotype can lead to Hb H disease. By molecular analysis, we established that this case fits the characteristic of an α(+) thalassemia genotype.
Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Guangxi 535099, PR China. Electronic address: lab@longju.net.
Ju
J
Long
Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Guangxi 535099, PR China.
Shanhuo
S
Yan
Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Guangxi 535099, PR China.
Kegan
K
Lao
Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Guangxi 535099, PR China.
Wanrong
W
Pang
Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Guangxi 535099, PR China.
Xuehe
X
Ye
Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Care Hospital, Guangxi 535099, PR China.
Lei
L
Sun
D000328:Adult; D001483:Base Sequence; D004909:Erythrocyte Indices; D005260:Female; D023061:Gene Order; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D005810:Multigene Family; D010375:Pedigree; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D055815:Young Adult; D055542:alpha-Globins / Q000235:genetics*; D017085:alpha-Thalassemia / Q000175:diagnosis* / Q000235:genetics*
D055542:alpha-Globins
-α(21.9); Gap PCR; Qinzhou type deletion; Thalassemia; α(+) thalassemia