The present invention relates to a method of identification and quantification of proteins, isoforms of angiotensin I converting enzymes (ACE), 190-kDa, specially of 90kDa in tissues, cells and biological fluids, specially in urine, genetic marker and prognostic agent of hypertension and primary or secondary renal lesion and kit for using in the diagnosis, risk stratification and therapeutical decision in arterial hypertension. One the aims of the present invention is to check the potential of the 90 kDa isoform as a hypertension genetic marker isoform and as a prognostic for hypertension.