After drainage of large volumes of ascitic fluid (especially > 5 L), plasma volume expansion is recommended to avoid paracentesis-induced circulatory dysfunction (PICD), a severe syndrome due to the acute worsening of effective hypovolemia and the consequent increase in plasma renin activity, leading to renal failure, severe hyponatremia, hepatic encephalopathy (HE), and eventually death [25]. This evidence concerns the gene REN and Hyponatremia.