Analysis of clinical phenotype of a α2-globin gene mutation -IVS-Ⅱ-55 (T→G)

Yumin LI; Yaqiong Chen; Shuilan Zhang; Lijuan Kan; Bing Zhang; Huamei Tang; Xiuming Zhang

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Analysis of clinical phenotype of a α2-globin gene mutation -IVS-Ⅱ-55 (T→G)

VernacularTitle:α2珠蛋白基因突变IVS-Ⅱ-55（T→G）的临床表型分析
Author: Yumin LI ^{1
,

2} ; Yaqiong CHEN ^{1
,

2} ; Shuilan ZHANG ^{1
,

2} ; Lijuan KAN ^{1
,

2} ; Bing ZHANG ^{1
,

2} ; Huamei TANG ^{1
,

2} ; Xiuming ZHANG ^{1
,

2}
Author Information

1. Department of Clinical Laboratory, Shenzhen Luohu District People&prime
2. s Hospital
Publication Type:Journal Article
Keywords: α-thalassemia; α-globin gene; IVS-Ⅱ-55; point mutation; phenotype
From: Chinese Journal of Clinical Laboratory Science 2019;37(2):105-108
CountryChina
Language:Chinese
Abstract: Objective:To identify a α-globin gene mutation-IVS-Ⅱ-55 (T→A) and analyze hematological characteristics of IVS-Ⅱ-55 (T→G) carriers.
Methods:The peripheral blood samples were collected from the members of five family and three sporadic IVS-Ⅱ-55(T→G) carriers for the analysis of RBC parameters and hemoglobin electrophoresis. Gap-PCR, PCR-RDB (reverse dot blot) and DNA sequencing were carried out for the identification of gene deletion and mutation of α-globin and β-globin.
Results:The results of RBC parameters of five infant probands which presented with microcytic hypochromic anemia were below the normal reference interval. One of the adult carriers of IVS-Ⅱ-55 (T→G) heterozygote alone presented with microcytic hypochromic anemia, and the others showed normal RBC parameters. The hematological phenotype index (MCV, MCH and HbA 2 ) of one adult carrying a compound heterozygote for IVS-Ⅱ-55 (T→G) and βCD27-28M/N were 65.0 fL, 20.3 pg and 5.8% respectively. The hematological phenotype index (MCV, MCH, HbA 2 and HbF) of one adult carrying a compound heterozygote for IVS-Ⅱ-55 (T→G) and SEA-HPFH were 81.9 fL, 26.5 pg, 3.0% and 29.0% respectively. The HbA 2 levels of all carriers of IVS-Ⅱ-55 (T→G) heterozygote alone were in normal range. No abnormal hemoglobin band was detectable on hemoglobin electrophoresis for all the carries.
Conclusion:The carriers of IVS-Ⅱ-55(T→G) heterozygote alone were asymptomatic. The phenotype of compound heterozygote for β-thalassemia was similar to that of β-thalassemia alone.
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