| 翻訳と辞書 |
| Alpha-thalassemia ： ウィキペディア英語版 |
Alpha-thalassemia
Alpha-thalassemia (α-thalassemia, α-thalassaemia) is a form of thalassemia involving the genes HBA1 and HBA2. Alpha-thalassemia is due to impaired production of alpha chains from 1,2,3, or all 4 of the alpha globin genes, leading to a relative excess of beta globin chains. The degree of impairment is based on which clinical phenotype is present (how many genes are affected).
==Epidemiology==
The worldwide distribution of inherited alpha-thalassemia corresponds to areas of malaria exposure, suggesting a protective role for alpha-thalassemia against the more severe manifestations of malaria. Thus, alpha-thalassemia is common in sub-Saharan Africa, the Mediterranean Basin, the Middle East, South Asia, and Southeast Asia, and different genetic subtypes have variable frequencies in each of these areas.〔Bernini LF. Geographic distribution of alpha thalassemia. In: Steinberg M, Forget B, Higgs D, et al., eds. Disorders of hemoglobin. New York, NY: Cambridge University Press; 2001:878-894.〕 The epidemiology of alpha-thalassemia in the US reflects this global distribution pattern. The most common form of alpha(+) thalassemia seen in the US is due to the -alpha(3.7) deletion, a single alpha-globin gene deletion, and is present in approximately 30% of African Americans. However, even in the homozygous state this disorder will result only in a mild microcytic anemia. The more serious clinical disorders of Hb H and Hb Bart hydrops fetalis syndrome, although found throughout the US today, are more common in the Western US and have dramatically increased in prevalence in the past 2 decades due to increased Asian immigration.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Alpha-thalassemia」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|