REN Gene

REN-related kidney disease is an inherited condition that affects kidney function. This condition causes slowly progressive kidney disease that usually becomes apparent during childhood. As this condition progresses, the kidneys become less able to filter fluids and waste products from the body, resulting in kidney failure. Individuals with REN-related kidney disease typically require dialysis (to remove wastes from the blood) or a kidney transplant between ages 40 and 70.

People with REN-related kidney disease sometimes have low blood pressure. They may also have mildly increased levels of potassium in their blood (hyperkalemia). In childhood, people with REN-related kidney disease develop a shortage of red blood cells (anemia), which can cause pale skin, weakness, and fatigue. In this disorder, anemia is usually mild and begins to improve during adolescence.

Many individuals with this condition develop high blood levels of a waste product called uric acid. Normally, the kidneys remove uric acid from the blood and transfer it to urine so it can be excreted from the body. In REN-related kidney disease, the kidneys are unable to remove uric acid from the blood effectively. A buildup of uric acid can cause gout, which is a form of arthritis resulting from uric acid crystals in the joints. Individuals with REN-related kidney disease may begin to experience the signs and symptoms of gout during their twenties.

Renal tubular dysgenesis is a severe kidney disorder characterized by abnormal development of the kidneys before birth. In particular, kidney structures called proximal tubules are absent or underdeveloped. These structures help to reabsorb needed nutrients, water, and other materials into the blood and excrete everything else into the urine. Without functional proximal tubules, the kidneys cannot produce urine (a condition called anuria).

Fetal urine is the major component of the fluid that surrounds the fetus (amniotic fluid), and anuria leads to decreased amniotic fluid levels (oligohydramnios). Amniotic fluid helps cushion and protect the fetus and plays a role in the development of many organs, including the lungs. Oligohydramnios causes a set of abnormalities called the Potter sequence, which includes distinctive facial features such as a flattened nose and large, low-set ears; excess skin; inward- and upward-turning feet (clubfeet); and underdeveloped lungs.

Renal tubular dysgenesis also causes severe low blood pressure (hypotension). In addition, bone development in the skull is abnormal in some affected individuals, causing a large space between the bones of the skull (fontanelles).

As a result of the serious health problems caused by renal tubular dysgenesis, affected individuals usually die before birth, are stillborn, or die soon after birth from respiratory failure. Rarely, with treatment, affected individuals survive into childhood. Their blood pressure usually normalizes, but they quickly develop chronic kidney disease, which is characterized by reduced kidney function that worsens over time.