Genetic dissection of the syndrome X in the rat

In 1988, Reaven used the term syndrome X to describe a relation between several disorders including hypertension, dyslipidemia, impaired glucose tolerance, obesity, and coronary heart disease. Despite a number of studies dealing with syndrome X, its genetic basis remains poorly understood. Regarding the complexity of this syndrome, it is important to use animal models developing the traits of the disease. Here we show a genetic dissection of syndrome X in the WOKW rat, an animal model of genetically determined syndrome X. We found a major quantitative trait locus (QTL) for glucose metabolism on chromosome 3 and further QTLs influencing obesity and body weight on chromosomes 1 and 5. Genetic determinants of dyslipidemia were mapped to chromosomes 4 and 17. In addition, suggestive linkage for serum insulin was found on chromosome 1 to the region previously shown to be associated with type-1 diabetes mellitus. This is the first study demonstrating independent genetic factors influencing traits of the syndrome X in the rat as well as a possible genetic relationships between syndrome X and diabetes mellitus. Moreover, regarding the close similarities between WOKW rat and human syndrome X, the study could help in a search of genetic factors involved in this complex metabolic disorder in human.