The gene for renin, previously mapped to human chromosome 1, was further localized to 1q12----qter using human-mouse somatic cell hybrid DNAs. The renin DNA probe used (lambda HR5) could detect a HindIII restriction fragment length polymorphism. When used in studies of 12 informative families, no linkage could be found between the renin gene and Charcot-Marie-Tooth disease. Furthermore, an association of any renin allele with hypertension was not apparent.