Boniotto Michele, Ventura Mario, Eskdale Joyce, Crovella Sergio, Gallagher Grant
Department of Oral Biology, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103-2714, USA.
Genet Test. 2004 Fall;8(3):325-7. doi: 10.1089/gte.2004.8.325.
Defensins constitute a primary mechanism in the innate immune system of humans and all mammals. Defensins are short, processed peptide molecules that are classified by structure into three groups: alpha-defensins, beta-defensins and theta-defensins. In humans, four beta-defensins have been described so far, corresponding to the products of the genes DEFB1 (hBD1, NM_005218), DEFB4 (hBD2, NM_004942.2), DEFB103 (hBD3, NM_018661), and DEFB104 (hBD4, NM_080389), respectively. All these genes have been mapped to chromosome 8p22-23. Much interest has been shown in genetic variation in the population at defensin loci to understand individual differences in disease susceptibility and severity. In this study, we have used an electronic search and then fluorescence in situ hybridization (FISH) on elongated chromosomes to demonstrate that the region containing the DEFB4 gene is duplicated on human chromosome 8p, making difficult the discovery of new SNPs in this gene and compromising the assessment of their allelic distribution in various ethnic populations for disease association studies.
防御素是人类和所有哺乳动物先天免疫系统中的一种主要机制。防御素是经过加工的短肽分子，根据结构可分为三类：α-防御素、β-防御素和θ-防御素。在人类中，目前已描述了四种β-防御素，分别对应于基因DEFB1（hBD1，NM_005218）、DEFB4（hBD2，NM_004942.2）、DEFB103（hBD3，NM_018661）和DEFB104（hBD4，NM_080389）的产物。所有这些基因都已定位到8号染色体的p22 - 23区域。人们对防御素基因座上的群体遗传变异表现出浓厚兴趣，以了解疾病易感性和严重程度的个体差异。在本研究中，我们先进行了电子搜索，然后对拉长的染色体进行荧光原位杂交（FISH），以证明包含DEFB4基因的区域在人类8号染色体的p臂上存在重复，这使得在该基因中发现新的单核苷酸多态性（SNP）变得困难，并影响了在各种种族群体中评估其等位基因分布以进行疾病关联研究。
