KLK4 and hydrops fetalis: Kallikreins (EC 3.4.21.8) comprise a subgroup of the serine protease family and areknown to have several physiological functions, including the control of blood pressure,coronary artery perfusion, electrolyte balance, inflammation, and other diversephysiological processes2,7-9.Our group has demonstrated that urinary hK1-specific amidase activity is significantlyreduced in hypertension and HF patients3,6.