Objective: To investigate the gene diagnosis and phenotypes analysis for a couple with β-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 β-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 β-globin gene, existed in pregnant woman, while her husband carried a rare mutation CD29 (c.90 C>T) of β-globin gene. The prenatal diagnosis indicated that the fetus inherited with mutation from the parents, fetus genotype was βIVS-Ⅱ-6541/βCD29.
Conclusion: The CD29(C>T) mutation of β-globin gene has been identified in Chinese population first. Although this mutation type is symonymous mutation, but its carrier displays phenotype of β-thalaessmia. Therefore, the attention to this mutation should be paid considering the genetic risk. It contributes to genetic counseling and prenatal gene diagnosis.
题目: 一种罕见的同义突变导致的β-地中海贫血的基因诊断和表型分析.
目的: 对血常规和血红蛋白电泳筛查结果提示疑为β-地中海贫血携带者的孕妇及其丈夫进行β-地中海贫血基因诊断，鉴定其表型并对胎儿进行产前基因诊断.
方法: 采用聚合酶链式反应-反向点杂交（PCR-RDB）方法及DNA测序方法分析并鉴定孕妇及其丈夫的外周血和孕妇的羊水样本的β-珠蛋白基因突变.
结果: 检测到孕妇本人为常见的β-珠蛋白基因IVS-Ⅱ-654 (C>T)位点杂合突变，其丈夫携带一种罕见β-珠蛋白基因CD29 (c.90 C>T)位点杂合突变，产前基因诊断出胎儿基因型为βIVS-Ⅱ-6541/βCD29.
结论: 本研究在中国人群中确切基因鉴定出β-珠蛋白基因CD29 (c.90 C>T)突变，此突变类型虽为同义突变但其携带者表现为β+-地中海贫血表型。考虑遗传风险应对此类同义突变给予重视，尤其对指导遗传咨询和产前基因诊断有重要意义.