Abstract: Disclosed is a method for determining a genetic predisposition to hypertension, end stage renal disease due to hypertension, non-insulin dependent diabetes mellitus, end stage renal disease due to non-insulin dependent diabetes mellitus, breast cancer, lung cancer or prostate cancer by detecting the presence or absence of single nucleotide polymorphisms in the nitric oxide synthase gene. Also disclosed are kits for detecting the presence or absence of the single nucleotide polymorphisms, methods for the treatment and/or prophylaxis of diseases, conditions, or disorders associated with the single nucleotide polymorphisms.