Renal tubular dysgenesis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 5, 2016
StartDiseasesRenal tubular dysgenesis

Renal tubular dysgenesis is a condition that occurs in the fetus caused by genetics and certain medications. The kidneys of the fetus develop abnormally, which causes a deficiency in the amount of amniotic fluid present in the womb. Very few babies with this condition live past the age of two. This condition is also known as Allanson Pantzar McLeod syndrome and autosomal-recessive renal tubular dysgenesis.

Contents

Definition & Facts

Renal tubular dysgenesis involves underdeveloped proximal tubules, which are tubes that reabsorb water and nutrients. The tubules also excrete harmful substances into the urine to be expelled from the body. When the proximal tubules are not working properly, the kidneys do not produce urine. In addition, there is severely low blood pressure (hypotension) associated with this condition.

Renal tubular dysgenesis is a severe condition. The fetus often dies before birth, is stillborn, or dies soon after birth due to respiratory failure. In some cases, those with renal tubular dysgenesis survive birth. Their blood pressure will rise to normal levels, but they develop chronic kidney disease. The ability of the kidneys to function deteriorates over time.

Symptoms & Complaints

The symptoms are usually detected during pregnancy with an ultrasonography. The fetus will have underdeveloped or missing proximal tubules which means that the mother will have a low amount of amniotic fluid protecting the womb.

Some fetuses with renal tubular dysgenesis have abnormal bone development in the skull. One indicator that renal tubular dysgenesis is likely to occur is if it is known that an older sibling was born with a low amount of amniotic fluid in the womb.

Babies who survive the birthing process will have trouble breathing, flat facial features and they will have little to no urine output.

Causes

Renal tubular dysgenesis is caused by abnormalities in kidney development before birth. When the fetus is in the womb, it is surrounded by amniotic fluid. Because the kidneys are malformed, it isn't able to produce sufficient amounts of fetal urine. Fetal urine is the main component in amniotic fluid. This lack of amniotic fluid sets the Potter sequence into motion: a series of abnormalities that cause changes in the fetus. These traits include a flattened nose, large ears, excessive amounts of skin, club feet, and lungs that are underdeveloped.

Renal tubular dysgenesis is often caused by genetic mutations. Affected genes include AGTR1, ACEAGT, and REN which damages the protein, angiotensin II. This protein helps balance electrolytes, regular blood pressure, and develop the kidneys in utero. It is generally inherited via autosomal recessive inheritance.

There are are also certain medications used to treat high blood pressure (hypertension) that can cause the disease in pregnant women. Renal tubular dysgenesis can also be caused by cardiovascular disease, congenital hemochromatosis, and in select cases, twin-to-twin transfusion syndrome, a complication of pregnancy with twins.

Diagnosis & Tests

The doctor will inquire about the patient's family history of renal tubular dysgenesis. The physician will want to know what medications the mother is on, as there are certain drugs that are linked to renal tubular dysgenesis.

The doctor will check blood pressure, as severely low blood pressure (hypotension) is often attributed to or associated with the condition. When doing an ultrasound, medical technicians routinely check the volume of amniotic fluid present in the womb. When it is low, they may suspect renal tubular dysgenesis.

If it is suspected, the physician will order genetic testing of the fetal cells. During the ultrasound, they will get a close look at the kidneys to look for development issues and they will check the skull for gaps or abnormalities. 

Treatment & Therapy

For babies born with renal tubular dysgenesis, they will require constant care. They will likely need mechanical ventilation as they often have great difficulty breathing normally. They will need blood transfusions.

They might require peritoneal dialysis to help their system remove waste. Parents should prepare for extensive hospital stays and will need to read up on the condition to learn the ways in which the child will need to be treated.

This condition is fatal. Parents should seek counseling to help deal with all of the issues that arise. There will be tough decisions to be made and the parents will need emotional support to get through it. 

Prevention & Prophylaxis 

The inherited forms of renal tubular dysgenesis cannot be prevented. Parents who are genetically at risk of having a child with this condition are advised to seek genetic counseling so they can understand the risks before they conceive.

Acquired renal tubular dysgenesis is preventable through avoiding certain medications that lower high blood pressure in pregnant women.