EDN1 and Hypertension: The human ET-1 gene was assigned to chromosome 6, and spans approximately 5.5 kb with 5 exons and 4 introns.11,12 Some epidemiologic studies analyzing the relationship between some polymorphisms in this locus and hypertension have been performed as case-control association studies.6,13-18 Moreover, the relationship between a polymorphism in the ET-1 gene and ventricular arrhythmia has been reported.19