Bierbaum S, Superti-Furga A, Heinzmann A
Centre for Pediatrics and Adolescent Medicine, University of Freiburg, Germany.
Int J Immunogenet. 2006 Jun;33(3):201-4. doi: 10.1111/j.1744-313X.2006.00597.x.
In humans, two types of chitinases have been identified: chitotriosidase I (CHIT1) and acid mammalian chitinase (AMCase). They are enzymes that cleave chitin, a polysaccharide contained in many different human parasites. So far, only little is known about their function in human and especially in human diseases. Recently we have described association of polymorphisms of AMCase with bronchial asthma in a pediatric population. In this study we were interested in whether CHIT1 is also involved in the genetics of asthma. The amino acid variants Gly102Ser and Ala442Gly, as well as a 24 bp duplication within CHIT1, were typed by means of restriction fragment length polymorphisms on 322 children with asthma and 270 randomly chosen adult controls. Statistical analyses made use of the Armitage's trend test; haplotypes were calculated by FAMHAP and FASTEHPLUS. The amino acid variants showed no association with bronchial asthma. The 24 bp duplication, previously shown to completely demolish CHIT1 activity, was also evenly distributed between asthmatics and controls. Finally, the haplotype showed no association with the disease. We conclude from our results that CHIT1 does not play a major role in the development of bronchial asthma in Caucasian children. The results might also imply that the two human chitinases that have been identified so far have quite distinct functions in human diseases even though they have the same substrate.
在人类中，已鉴定出两种类型的几丁质酶：几丁三糖酶I（CHIT1）和酸性哺乳动物几丁质酶（AMCase）。它们是能够裂解几丁质的酶，几丁质是一种存在于许多不同人体寄生虫中的多糖。到目前为止，关于它们在人类尤其是人类疾病中的功能知之甚少。最近我们描述了AMCase基因多态性与儿科人群支气管哮喘的关联。在本研究中，我们感兴趣的是CHIT1是否也参与哮喘的遗传学。通过限制性片段长度多态性对322名哮喘儿童和270名随机选择的成年对照进行CHIT1内的氨基酸变体Gly102Ser和Ala442Gly以及24 bp重复的分型。统计分析采用阿米蒂奇趋势检验；单倍型通过FAMHAP和FASTEHPLUS计算。氨基酸变体与支气管哮喘无关联。先前已证明能完全破坏CHIT1活性的24 bp重复在哮喘患者和对照之间也均匀分布。最后，单倍型与疾病无关联。我们从结果中得出结论，CHIT1在白种人儿童支气管哮喘的发生中不发挥主要作用。结果也可能意味着，尽管已鉴定出的两种人类几丁质酶具有相同的底物，但它们在人类疾病中的功能却截然不同。
