[Differential Diagnosis of Three Commonest Deletion ß-Thalassemia in Chinese].

OBJECTIVE: To analyze the hematological characteristics of Chinese Gγ+(Aγδß)0-thalassemia，SEA-HPFH and Taiwan type ß-thalassemia. METHODS: Hemoglobin electrophoresis and blood routine test were used to analyze the hematological indexes of all peripheral blood samples，PCR-Flow fluorescent hybridization and Gap-PCR were used to detect the globin gene mutations and the data were analyzed statistically. RESULTS: The 3 types of deletion ß- Thalassemia patients were showed as hypochromic small cell anemia. The MCH and MCV values of Taiwan type ß-thalassemia patients were the lowest. The results of hemoglobin electrophoresis showed that the increasing of HbF was found in all of the 3 types. Except for the decreasing of Hb A2 in Chinese Gγ+(Aγδß)0-thalassemia，the levels of Hb A2 in the other two deletion ß-thalassemia patients were significantly increased. Except for Hb, there were significant differences in MCV, MCH, Hb A2 and HbF between Chinese Gγ+(Aγδß)0-thalassemia and SEA-HPFH(P<0.001). CONCLUSION: Through analyze the hematological characteristics, it can be provide that the guidance for the differential diagnosis and genetic consultation of the three commonest deletion ß-thalassemia in Chinese.

[Genetic Effect Analysis of ß-globin Gene 3'UTR+101G>C (HBB:c. *233G>C) Variant].

OBJECTIVE: To investigate whether ß-globin gene 3'UTR+101G>C (HBB:c.*233G>C) variant has genetic effect and provide basis for gene diagnosis and genetic counseling. METHOD: Whole blood cell analysis and capillary zone electrophoresis (CZE) were used to analyze the hematological indexes. The most frequent 23 mutations in southern Chinese individuals were routinely measured by PCR-flow fluorenscence immunmicrobeads assay. Sanger sequencing was used to detect the other variants of ß-globin gene (HBB). RESULTS: In 463 cases, a total of 7 cases with HBB:c.*233G>C variant were detected, among them 4 cases carried other pathogenic variants of HBB gene (2 cases were in trans, 2 cases were in cis), who had typical hematological characteristics of mild ß-thalassemia, and 3 cases also carried abnormal hemoglobin variation, but did not have hematological characteristics of ß-thalassemia. CONCLUSION: The study shows that HBB:c.*233G > C variant has no obvious genetic effect and should be a benign polymorphism.

[Hematological Analysis and Diagnosis of Two Rare Abnormal Hemoglobin].

OBJECTIVE: To analyze the hematological characteristics of Hb Broomhill and Hb Hornchurch, and prenatal diagnosis should be carried out in two families. METHODS: RBC parameters and hemoglobin electrophoretogram were analyzed on the peripheral blood of all patients, and amniotic fluid was collected for prenatal diagnosis. PCR-Flow fluorescent hybridization and Sanger sequencing were performed for gene diagnosis of thalassemia. RESULTS: Three cases of Hb Broomhill were detected, including 2 cases with common SEA α-thalassemia, which was characterized by hypochromic microcytic mild anemia, the capillary electrophoregram revealed a tiny shoulder peak before the Hb A peak; 1 case was diagnosed as Hb Hornchurch combined with ß-thalassemia, which also showed mild anemia. Hemoglobin electrophoretogram showed an abnormal hemoglobin variant peak at Hb A2 zone. CONCLUSION: The carriers of Hb Broomhill and Hb Hornchurch do not have microcytic hypochromic anemia, which do not aggravate the hematological symptoms, such as anemia when being combined with thalassemia of the same type.

[Gene Diagnosis and Phenotypic Analysis of ß-Thalassemia Caused from a Rare Synonymous Mutation CD29 (C>T)].

OBJECTIVE: To investigate the gene diagnosis and phenotypes analysis for a couple with ß-thalassemia suspected from of blood routine test and hemoglobin electrophoresis, as well as the prenatal gene diagnosis of the fetus. METHODS: The gene mutation of ß-globin in the samples of peripheral blood of pregnant woman and her husband, as well as amniotic fluid of pregnant woman were analyzied and identified by using PCR-RDB and Sanger sequencing. RESULTS: The detection showed that the heterozygote mutation of IVS-Ⅱ-654 (C>T), which is common mutation of ß-globin gene, existed in pregnant woman, while her husband carried a rare mutation CD29 (c.90 C>T) of ß-globin gene. The prenatal diagnosis indicated that the fetus inherited with mutation from the parents, fetus genotype was ßIVS-Ⅱ-6541/ßCD29. CONCLUSION: The CD29(C>T) mutation of ß-globin gene has been identified in Chinese population first. Although this mutation type is symonymous mutation, but its carrier displays phenotype of ß-thalaessmia. Therefore, the attention to this mutation should be paid considering the genetic risk. It contributes to genetic counseling and prenatal gene diagnosis.

[Value of Analyzing Hemoglobin A2 by ROC Curve for Screening Thalassemia].

OBJECTIVE: To investigate the value of hemoglobin A2(HbA2) for screening thalassemia. METHODS: A total of 2 000 adults' peripheral blood samples from Guangdong Women and Children Hospital from June 2013 to January 2014 were collected. The hemoglobin A2 (HbA2) level was analyzed by the full automatic capillary electrophoresis technique, and the genotypes of thalassemia were detected. RESULTS: The optimal cutoff values of HbA2 for screening silent α-thalassemia, α-thalassemia trait, intermedia α-thalassemia and ß-thalassemia trait were 2.85%, 2.65%, 2.25% and 3.45%, respectively; the areas under receiver operator characteristic (ROC) curve were 0.709, 0.839, 0.979 and 0.997 respectively; the sensitivities were 0.481, 0.721, 0.953 and 0.994, and the specificities were 0.846, 0.837, 0.929 and 0.969 respectively. CONCLUSION: The optimal cutoff values of HbA2 for screening different type of thalassemia based on our laboratory data are established by using ROC curve. According to the area under ROC curve, a satisfactory accuracy for screening intermedia α-thalassemia and ß-thalassemia trait can be achieved by detecting hemoglobin A2 level.