REN

The REN gene provides instructions for making a protein called renin, which is produced in the kidneys. This protein is part of the renin-angiotensin system, which regulates blood pressure and water levels in the body. Renin converts a molecule called angiotensinogen into angiotensin. Angiotensin causes blood vessels to narrow (constrict), which results in increased blood pressure. Angiotensin also stimulates the production of the hormone aldosterone, which causes the kidneys to retain salt and water. An increased amount of fluid in the body also increases blood pressure.

REN-related kidney disease - caused by mutations in the REN gene

At least two mutations in the REN gene have been found to cause REN-related kidney disease. One of these mutations results in the removal of a single protein building block (amino acid) called leucine at position 16 in the protein (written as Leu16del). The other mutation replaces the leucine at position 16 with the amino acid arginine (written as Leu16Arg or L16R). Individuals with REN-related kidney disease have one mutated REN gene and one normal gene in each cell. The mutations that cause REN-related kidney disease result in the production of an abnormal protein that is toxic to the kidney cells that normally produce renin. The renin-producing cells gradually die off, which disrupts the renin-angiotensin system and causes progressive kidney disease.

other disorders - caused by mutations in the REN gene

At least five mutations in the REN gene have been found to cause a severe kidney disorder called renal tubular dysgenesis. In this disorder, the kidneys develop abnormally before birth and cannot produce urine. Fetal urine is a normal component of the fluid that surrounds the fetus (amniotic fluid). One of the functions of amniotic fluid is to promote the growth and development of the lungs. Fetuses with renal tubular dysgenesis have decreased amniotic fluid levels, resulting in underdeveloped lungs. This condition also causes severe low blood pressure (hypotension). As a result of these serious health problems, affected individuals usually die before birth, are stillborn, or die soon after birth from respiratory failure.

Renal tubular dysgenesis can be caused by mutations in both copies of any of the genes in the renin-angiotensin system. Most REN gene mutations that cause this disorder prevent the production of any renin protein, which results in a nonfunctional renin-angiotensin system. Without this system, the kidneys do not develop normally and cannot control blood pressure.