Children's Hospital Colorado

Alport Syndrome

What is Alport syndrome?

Alport syndrome is a condition affecting the kidneys that results in blood and extra protein in the urine and often leads to decreased kidney function over time. This decrease in kidney function can be severe enough to eventually require dialysis or kidney transplantation. Alport syndrome can also affect the eyes and ears, which can result in some degree of hearing loss.

What causes Alport syndrome?

Alport syndrome is caused by a genetic mutation that can be passed down through the parents. The affected gene that causes Alport syndrome, COL4A5, helps to create proteins that form the filters in the kidneys. The same protein, collagen, is also used to create tissues in the eyes and ears, which is why Alport syndrome can also affect them.

Who gets Alport syndrome?

The gene mutations responsible for the development of Alport syndrome are found on the X chromosome. Because males only have one copy and females have two, females have a better chance of having at least one healthy X chromosome. That means that Alport syndrome mostly affects males and it affects them more severely than females. While females can "carry" the mutation and it may affect them mildly, it is rare to see severe cases of Alport syndrome in females.

Based on how the X chromosome is affected, Alport syndrome is divided into three separate genetic types:

  • X-linked Alport syndrome (XLAS) is the most common. In this type, affected males typically have more severe cases than affected females.
  • Autosomal recessive Alport syndrome (ARAS) is the second most common. In this type, the severity of disease in affected males and females is similar.
  • Autosomal dominant Alport syndrome (ADAS) is the least common. In this type, the disease is severe and affects males and females equally.

What are the signs and symptoms of Alport syndrome?

Blood in the urine (either visible or detected by dipstick testing) is often an initial sign of Alport syndrome. Because the mutations causing Alport syndrome are usually inherited, there is frequently also a family history of the disease, especially in male relatives.

About 50% of untreated males with XLAS develop kidney failure by age 25. By the age of 40, about 90% develop kidney failure and by age 60, nearly 100% develop kidney failure. Females with XLAS do not usually see signs of decreased kidney function until later in life. They may not develop decreased kidney function or failure at all, but the risk increases as they grow older. Both males and females with ARAS can develop kidney failure early, often in their teenage years or early adulthood.

The signs and symptoms of ADAS tend to develop more slowly, and decreased kidney function does not usually start until well into adulthood. Individuals with Alport syndrome can also develop progressive hearing loss of varying levels. Eye problems do not usually result in impaired vision.

Decreased kidney function means that the kidneys are not filtering toxins from the blood as they should. Some signs and symptoms of decreased kidney function include:

  • Blood in the urine
  • Abdominal swelling due to fluid buildup
  • Low urine output
  • High blood pressure
  • Weakness and fatigue
  • Malaise (a general feeling of discomfort or illness)
  • Fever
  • Weight loss

What tests are used to diagnose Alport syndrome?

Our doctors may strongly suspect Alport syndrome based on a family history and combined findings of blood in the urine (possibly with some eventual decrease in kidney function on laboratory testing) and impaired hearing. A kidney biopsy can confirm the diagnosis.

A kidney biopsy is a procedure in which we remove a small piece of kidney tissue and examine it under a microscope. Genetic testing may also be helpful in making or confirming a diagnosis of Alport syndrome. We can obtain a sample for a genetic test from a simple saliva swab or by using a blood sample.

What to expect from a kidney biopsy

At Children's Hospital Colorado, we perform a kidney biopsy as an outpatient procedure. We either use sedation to calm your child, or we use full anesthesia, which puts them completely to sleep to eliminate stress and pain as much as possible.

To get the tissue sample, we insert a needle through the back onto the surface of the kidney. Using real-time ultrasound to help us guide the needle, we remove a few small pieces of kidney tissue. We then examine the tissue under a microscope.

After the procedure, which usually lasts about one hour, we will wake your child and monitor them for several hours to ensure any bleeding caused by the biopsy has stopped. If there are no complications, they may leave the hospital. We recommend they avoid strenuous activities for 7 to 10 days. Once the biopsy results are available a few days after the procedure, we discuss them with you and your child and work with you to develop the best treatment plan.

Why choose us to test for Alport syndrome?

From using smaller needles to fit their smaller veins, to using distraction methods like virtual reality headsets, all our tests are designed for children. Our child life team helps explain the procedure in a way that your child understands, with the goal of lowering anxiety and making the hospital experience less stressful.

Coming to Children's Colorado means that our nurses, doctors and anesthesiologists have all been specially trained in pediatric medicine, which means they understand how kids are incredibly different from adults.

How is Alport syndrome treated?

The abnormalities in the protein building blocks of the kidney filters that occur in Alport syndrome are irreversible, which means there is no cure. Treatment is therefore supportive, aiming to minimize urinary protein losses, normalize high blood pressure when present and treat any complications caused by decreased kidney function.

Other than high blood pressure, these complications can include anemia (low red blood cell count), bone damage, high acid levels in the body and growth failure. If the decrease in kidney function becomes severe over time, dialysis and kidney transplantation are eventually required. Kidney transplantation provides your child with a healthy kidney that has normal building blocks, so it is the treatment of choice for patients whose own kidneys are failing because of Alport syndrome.

If there is associated hearing loss, we typically treat it with hearing aids. To do this, we collaborate with our Otolaryngology Department (ear, nose and throat), who are experts in treating hearing loss in children.

Why choose us for treatment of Alport syndrome?

Alport syndrome can sometimes go unnoticed throughout childhood. However, if we diagnose your child with Alport syndrome, our Kidney Center offers a complete array of management options, especially if there is some degree of decreased kidney function. The care team consists of specialized pediatric kidney doctors, nurses, dietitians, pharmacists, social workers and other pediatric specialists who enable us to provide complete and comprehensive care. For children with Alport syndrome who develop severe kidney failure, Children's Colorado also has the only pediatric dialysis and kidney transplant programs in the region.

  • The Alport Syndrome Foundation is an independent nonprofit organization that gives a voice to the Alport syndrome community. Their mission is to improve the lives of those affected by Alport syndrome through education, empowerment, advocacy and research.
  • The National Kidney Foundation (NKF) acts as a lifeline for all people affected by kidney disease. As pioneers of scientific research and innovation, NKF focuses on the whole patient through the lens of kidney health and strives to enhance lives through action, education and accelerating change.
  • The National Organization for Rare Diseases (NORD) is a nonprofit, patient advocacy organization dedicated to individuals with rare diseases such as Alport syndrome and the organizations that serve them. NORD is committed to the identification, treatment and cure of rare disorders through programs of education, advocacy, research and patient services.
  • The Genetic and Rare Disease (GARD) Information Center is a program of the National Center for Advancing Translational Sciences (NCATS) that provides access to current, reliable and easy-to-understand information about rare or genetic diseases like Alport syndrome.