SHORT COMMUNICATION The Werner Syndrome Gene and Global Sequence Variation G. Passarino,* , † ,1 P. Shen,‡ J. B. Van Kirk,* A. A. Lin,* G. De Benedictis,† L. L. Cavalli Sforza,* P. J. Oefner,‡ and P. A. Underhill * * Department of Genetics, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305; ‡Stanford Genome Technology Center, 855 California Avenue, Palo Alto, California 94304; and †Department of Cell Biology, University of Calabria, Arcavacata, 87030, Rende, Italy Received August 15, 2000; accepted September 29, 2000 We have identified a dense set of markers useful in association studies involving the Werner syndrome (WRN) gene. The homozygotic disruption of the WRN gene is the cause of Werner disease. In addition, this gene is likely to be involved in many complex traits, such as aging, or at least some of the traits and dis- eases related to age. To investigate the genetic varia- tion associated with the WRN gene, a sample of 93 individuals representing all the continents was ana- lyzed by denaturing high-performance liquid chroma- tography. A systematic survey of all 35 exons and flanking regions identified 58 single-nucleotide poly- morphisms, 15 of which fall in the coding region and cause 11 missense mutations. The resulting global nu- cleotide diversity was 5.226  10 4 , with a slight differ- ence between coding and noncoding regions. © 2001 Academic Press Werner syndrome (WRN) is an autosomal recessive progeroid disorder (3, 13). Patients prematurely dis- play age-related conditions, such atherosclerosis, can- cer, and osteoporosis. The median life span of patients is 47 years (3). This disorder is caused by homozygotic null mutations in the WRN gene (15). This gene lies on the short arm of chromosome 8 and is composed of 35 exons. The gene encodes a 1432-amino-acid protein with a central domain homologous to the RecQ family of DNA helicases (15). In contrast to other known RecQ-like helicases, the WRN protein displays both exonuclease and helicase activities in vitro (5). All the Werner syndrome mutations implicated in disease in- volve a truncation of the protein or a shift of the read- ing frame. Different mutations have been found to cause the disease in Caucasian and Japanese patients (10, 15, 16). Beyond its role in Werner syndrome, the WRN pro- tein is likely to be a risk factor involved in common diseases (2). For example, it has been proposed that the 1367Cys/Arg mutation could cause susceptibility to myocardial infarction (17). B lymphocyte cell lines from clinically normal heterozygous carriers exhibit in vitro features intermediate between those of null and nor- mal homozygotes (9). It is possible that the WRN pro- tein is involved in normal aging (15, 16). This inference is suggested by symptoms of Werner syndrome pa- tients and also by the finding that the yeast sgs1 pro- tein, which is homologous to WRN helicases, influences aging (12). An intriguing cooperation has been found between telomerase and the WRN protein: cooperation to prevent the aging of Werner syndrome fibroblasts (14). We have screened the WRN gene and the surround- ing genome region for single-nucleotide polymorphisms (SNPs). SNPs have proven valuable in the study of sequence variation in human genes (1, 4, 11). For ex- ample, SNPs facilitate the construction of dense, stable haplotypes for association and population affinity stud- ies. They may also contribute directly to genetic risk for common diseases as indicated by the common dis- ease– common variant hypothesis (4). Thus, under- standing WRN gene variability might be useful in de- termining whether or not this gene plays a role in other complex traits. To that end, we have performed a SNP search across the WRN gene region. All 35 exons and their respective flanking regions have been screened by denaturing high-performance liquid chromatography (DHPLC) (8) in a worldwide sample of 93 individuals. To determine correctly the ancestral allele, and to un- derstand better the evolution of the gene, we have sequenced the equivalent regions in one chimpanzee. A total of 58 SNPs were identified over the 12,839 bp surveyed, encompassing 3558 bp of coding sequence. All of the polymorphisms that we have found are listed in Table 1. Thirty-four nucleotide changes are transi- tions, and 20 are transversions; of the remaining 4, 3 are single-nucleotide deletions while 1 is an insertion. Among the 15 nucleotide changes that occurred in the 1 To whom correspondence should be addressed at Department of Genetics, Room M304, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305. Telephone: (650) 723-6506. Fax: (650) 725-1534. E-mail: g.passarino@stanford.edu. All articles available online at http://www.idealibrary.com on Genomics 71, 118 –122 (2001) doi:10.1006/geno.2000.6405 118 0888-7543/01 $35.00 Copyright © 2001 by Academic Press All rights of reproduction in any form reserved.