title: Evidence for duplication of the human defensin gene DEFB4 in chromosomal region 8p22-23 and implications for the analysis of SNP allele distribution.
abstract: 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.
authors.affiliation: Department of Oral Biology, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103-2714, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Boniotto
authors.forename: Mario
authors.initials: M
authors.lastname: Ventura
authors.forename: Joyce
authors.initials: J
authors.lastname: Eskdale
authors.forename: Sergio
authors.initials: S
authors.lastname: Crovella
authors.forename: Grant
authors.initials: G
authors.lastname: Gallagher
mesh_terms: D000483:Alleles; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D020440:Gene Duplication; D005787:Gene Frequency / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D020641:Polymorphism, Single Nucleotide; D023083:beta-Defensins / Q000235:genetics*
chemical_list: C106641:DEFB4A protein, human; D023083:beta-Defensins