碩士 / 高雄醫學大學 / 臨床醫學研究所 / 100 / 論文英文摘要
Alpha-thalassemia is one of the most common autosomal recessive disorders in the world and characterized by a microcytic hypochromic anemia. Alpha-thalassemia has a high prevalence rate in Southeast Asia area including Taiwan with a rate of 5%. A majority of the genetic defects of α-thalassemia are deletions of the α-globin genes. Normal individuals have four functioning α-globin genes and are defined as αα/αα. According to the defects of the α-globin, the clinical phenotypes of α-thalassemia could be divided into four groups. Individuals with loss of one α-globin gene (-α/αα) have 3 functional α-globin genes. Loss of one gene constitutes a silent carrier state without any clinical symptoms. Alpha thalassemia trait occurs with loss of two α-globin genes, namely -α/-α, --/αα. Such individuals are characterized with mild to moderate microcytic anemia. Individuals with hemoglobin (Hb) H disease show deletions of three α-globin genes. Such individuals are characterized with more severe anemia and splenomegaly. Lastly, the loss of four α-globin genes causes Hb Barts hydrops in individuals, which result in intrauterine death.
The initial laboratory examinations for the diagnosis of α-thalassemia include a complete blood cell count, red cell indices, iron status and hemoglobin electrophoresis. To identify the copy number of α-globin genes in α-thalassemia, we developed a novel method using multiplex polymerase chain reaction (PCR) in combination with the CE analysis.
Total 66 α-thalassemia patients with α-globin gene deletions including 6 with -α3.7 and 4 -α4.2 types of one-gene deletion, 27 with Southeast Asia type (- -SEA), 16 Filipino (- -FIL) type, 5 Thai (- -THAI) types of two-gene deletions, 7 Hb H disease with three-gene deletions, and 1 Hb Barts hydrops fetalis with four-gene deletions were included in this study. 46 normal controls were also obtained at Kaohsiung Medical University Hospital.
The copy number ratios of HBA1/KRIT1, HBA2/KRIT1, HBA1/CYBB and HBA2/CYBB were around 2/2, 2/2, 2/1 and 2/1 in normal male individuals, and around 2/2, 2/2, 2/2 and 2/2 in normal female individuals. The copy number ratios of HBA1/KRIT1, HBA2/KRIT1, HBA1/CYBB and HBA2/CYBB were around 2/2, 1/2, 2/1 and 1/1 in male patients, and around 2/2, 1/2, 2/2 and 1/2 in female patients with a genotype of one α-globin-gene deletion, -α/αα, α-thalassemia. The copy number ratios of HBA1/KRIT1, HBA2/KRIT1, HBA1/CYBB and HBA2/CYBB were around 1/2, 0/2, 1/2 and 0/2 in male patients, and around 1/2, 1/2, 1/2 and 1/2 in female patients with a genotype of two α-globin-gene deletions, --/αα, α-thalassemia. The copy number ratios of HBA1/KRIT1, HBA2/KRIT1, HBA1/CYBB and HBA2/CYBB were around 1/2, 0/2, 1/1 and 0/1 in patients and around 1/2, 0/2, 1/2 and 0/2 in female patients with a genotype of three α-globin-gene deletions, --/-α, α-thalassemia. There is no HBA1 and HBA2 copy number detection in a fetus with a four α-globin-gene deletions, --/--, hemoglobin Barts hydrops fetalis α-thalassemia.
In the present study, we established a rapid and efficient method to measure the copy number of two α-globin genes, HBA1 and HBA2, in α-thalassemia patients, determine low level of maternal DNA contamination in the fetus specimen for prenatal diagnosis and defect of rare multiplicated α-globin genes in the individuals. The proposed method provides a rapid detection of the common α-globin gene deletions. Sixty-six α-thalassemia patients and 46 normal controls were included in the present study. The obtained results showed good correlation with those obtained by gap PCR. Moreover, a low amount of maternal cell contamination in the fetus specimen for the prenatal diagnosis of hemoglobin Barts hydrops fetalis as well as the rare multiplicated α-globin genes can be identified using this method.
| Identifer | oai:union.ndltd.org:TW/100KMC05521003 |
| Date | January 2012 |
| Creators | Yu Mei Liao, 廖優美 |
| Contributors | Jan-Gowth Chang, 張建國 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 78 |
Page generated in 0.0128 seconds