A 24-bp duplication in exon 10 of human chitotriosidase gene from the sub-Saharan to the Mediterranean area:: role of parasitic diseases and environmental conditions
A 24-bp duplication in exon 10 of human chitotriosidase gene from the sub-Saharan to the Mediterranean area:: role of parasitic diseases and environmental conditions
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DOI：
10.1038/sj.gene.6364025
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发表时间：
2003-12-01
影响因子：
5
通讯作者：
Musumeci, S
中科院分区：
文献类型：
--
作者：
Malaguarnera, L;Simporè, J;Musumeci, S
人几丁糖苷酶(Chit)是几丁质酶家族的一员，由活化的巨噬细胞合成。最近，一种基因多态被发现是导致Chit活性普遍缺乏的原因，这种缺陷在不同的人群中经常遇到。我们分析了地中海和非洲地区一些民族的Chit基因，以评估Chit基因多态是否与环境特征的变化和寄生虫病的消失有关。在西西里岛和撒丁岛，外显子10重复24个碱基对的杂合子频率分别为44%和32.71%，而Chit缺陷者分别为5.45%和3.73%。相比之下，在贝宁和布基纳法索，这两个恶性疟疾和其他肠道寄生虫感染的中间流行区，Chit突变的发生率很低(分别为0%和2%)，没有人是Chit缺乏症纯合子。我们的结果提供了证据，即突变Chit基因的低频率或缺失可能代表了仍生活在不利环境条件下的种群的保护因素。本研究表明，寄生虫病的消失和环境条件的改善可能导致西西里岛、撒丁岛和其他地中海国家出现高比例的24BP突变，而在撒哈拉以南地区(贝宁和布基纳法索)，普遍存在的寄生虫病和较差的社会地位有助于维持野生型Chit基因。
Human chitotriosidase ( Chit) is a member of the chitinase family and it is synthesized by activated macrophages. Recently, a genetic polymorphism was found to be responsible for the common deficiency in Chit activity, frequently encountered in different populations. We analyzed the Chit gene in some ethnic groups from the Mediterranean and African areas, to evaluate whether the Chit gene polymorphism correlates with the changes in environmental features and the disappearance of parasitic diseases. We found a heterozygote frequency for the duplication of 24 bp in exon 10 of 44% in Sicily and 32.71% in Sardinia, whereas those homozygous Chit deficient were 5.45 and 3.73%, respectively. In contrast, in Benin and Burkina Faso, both mesoendemic regions for Plasmodium falciparum malaria and other infections due to intestinal parasites, a low incidence of Chit mutation was found ( heterozygous 0 and 2%, respectively) and no subject was homozygous for Chit deficiency. Our results provide evidence of the fact that the low frequency or the absence of mutant Chit gene may represent a protective factor in the population still living in disadvantaged environmental conditions. The present study suggests that the disappearance of parasitic diseases and the improved environmental conditions may have ensued the occurrence of a high percentage of 24- bp mutation in Sicily, in Sardinia and in other Mediterranean countries, whereas in the sub-Saharan regions ( Benin and Burkina Faso), the widespread parasitic diseases and the poor social status have contributed to maintenance of the wild-type Chit gene.