Werner syndrome protein 1367 variants and disposition towards coronary artery disease in Caucasian patients.

The leading causes of death for individuals with Werner syndrome (WS) are myocardial infarction (MI) and stroke. The WS gene encodes a nuclear protein with both helicase and exonuclease activities. While individuals with WS have mutations that result in truncated, inactive proteins, several sequence variants have been described in apparently unaffected individuals. Some of these gene polymorphisms encode non-conservative amino acid substitutions, and it is expected that the changes would affect enzyme activity, although this has not been determined. Two research groups have studied the Cys/Arg 1367 polymorphism (located near the nuclear localization signal) in healthy and MI patients. Their results suggest that the Arg allele is protective against MI. We have characterized the Cys (C) and Arg (R) forms of the protein and find no notable difference in helicase and nuclease activities, or in nuclear/cytoplasmic distribution. The frequency of the C/R alleles in healthy individuals and subjects with coronary artery disease (CAD) drawn from the Baltimore Longitudinal Study of Aging (BLSA) was also examined. There was no indication that the R allele was protective against CAD. We conclude that the C/R polymorphism does not affect enzyme function or localization and does not influence CAD incidence in the BLSA cohort.