What is Alport syndrome?

Alport syndrome is a rare genetic condition that can affect the kidneys and hearing. It can range from mild to severe and can vary between members of the same family. The condition is named after the doctor who first identified the condition in 1927, Dr Arthur Cecil Alport.

Alport syndrome is currently undergoing an international renaming process. Until a decision is reached, you may hear it referred to as ‘thin basement membrane nephropathy’, ‘autosomal dominant Alport syndrome’, ‘type IV collagen-associated kidney disease’ or ‘Alport spectrum nephropathy’.

Alport syndrome occurs when there is a problem with one of the important fibres that make up a membrane in the tiny filters of the kidneys. This makes the kidneys ‘leaky’ and affects their ability to filter the blood. Over time this can cause scarring and kidney damage. There is a similar membrane in the inner ear and 1 in 2 people with Alport syndrome have hearing issues, although for some this is very mild and not noticed.

Alport syndrome affects around 1 in 2,300 people in the UK. Outcomes have improved in recent years due to new treatments. Monitoring and early treatment greatly reduces the chance of developing kidney failure.

What are the signs and symptoms of Alport syndrome?

Hearing loss is often one of the first signs of Alport syndrome and is usually first noticed in boys around the age of ten.

Other symptoms of Alport syndrome include:

• Blood in the urine (haematuria) – the urine may look red or dark brown (like a cola drink). It does not cause any pain and may start after an infection such as a cold. The haematuria may be invisible to the naked eye but can be seen under a microscope (microscopic haematuria) or when tested by dipping a specially treated paper strip into your urine (urine dipstick).
• Protein in the urine (proteinuria) – this is likely to only be seen on a urine dipstick test, but if there is a lot of protein, the urine may look frothy.
• High blood pressure.

Most men with Alport syndrome develop kidney failure in their twenties or thirties.

Without treatment, around 1 in 5 women with Alport syndrome develop kidney failure by the age of 60. This risk can be reduced by monitoring and early treatment.

What causes Alport syndrome?

Alport syndrome is caused by a fault in one of three genes - COL4A3, COL4A4 or COL4A5 - that make one of the fibres (Collagen IV) that form the kidneys filtering system.

Without normal Collagen IV, the kidneys’ filtering membrane is weakened causing it to leak. The body will try to repair the weakened filters, however, over time the filters become scarred and can no longer function. Kidney function will then decline.

Collagen IV is also essential in the inner ear in the cochlear membrane. This transmits sound vibrations to the nerve sensors in the ear. The weakening of this membrane eventually leads to hearing loss.

How is Alport syndrome diagnosed?

Alport syndrome is usually diagnosed by:

• checking the urine for signs of kidney damage
• reviewing the family history for evidence of previous kidney problems
• testing the hearing, especially in boys

Genetic testing can confirm the diagnosis and a kidney biopsy may also be offered if the symptoms are unclear or if another diagnosis is possible.

The earlier the diagnosis the made, the better the chance of maintaining kidney function.

Does Alport syndrome affect other parts of the body?

Alport syndrome can cause hearing difficulties in boys. These are usually first noticed around the age of ten. A hearing test (audiogram) will likely show hearing loss for high-pitched sounds such as speech. The ability to hear lower sounds is less affected. Both ears are likely to be affected.

Once hearing loss has started, it usually gets gradually worse over the next ten years. Overall hearing loss is moderate, and it is unusual for someone with Alport syndrome to become completely deaf.

As children with Alport syndrome have normal hearing at birth, their speech develops normally.

Girls are rarely affected by early hearing loss but this may develop in middle age.

Some people with Alport syndrome also have problems with their eyes. These are usually minor and are easily treated. They tend to occur in adults rather than children and rarely lead to problems with vision. Small white flecks can sometimes be seen around the retina (the inner part) of the eye. These flecks do not affect the vision but can help with the diagnosis of Alport syndrome. In some cases, the lens of the eye becomes cone-shaped and cause short-sightedness.

Does Alport syndrome run in families?

Alport syndrome is usually inherited from one or both parents who pass on an affected copy of the COL4A3, COL4A4 and/or COL4A5 genes to their child.

De novo (new) variants occur in around 10-15 out of 100 cases of Alport syndrome, which means the variant is new and not inherited from either parent.

How is Alport syndrome treated?

Early treatment is important to help maintain kidney function and reduce the risk of developing kidney failure.

You will likely be prescribed a type of medicine called a renin-angiotensin system (RAS) blockade which can help to delay kidney failure by an average of 18 years if it is started while your kidney function is still high. This may be ramipril which is a type Angiotensin Converting Enzyme (ACE) inhibitor and works by reducing scarring in the kidneys so that they last longer. Angiotensin receptor blockers (ARBs) may be prescribed if ACE inhibitors do not work or you do not tolerate them.

SGLT2 inhibitors may also be prescribed to slow the progression of kidney disease.

Your medication may need to be temporarily adjusted if you are ill with a fever, vomiting or diarrhoea. Do not stop or change any of your medication without advice from your doctor or pharmacist.

Kidney function reduces slowly in people with Alport syndrome, so it is important to have regular health checks to monitor progress. These will include:

• urine tests to check the urine albumin-creatinine ratio (uACR)
• kidney function tests
• blood pressure measurements
• a full eye exam
• hearing tests

Cataract or lens surgery for people with Alport syndrome should be done in a specialist centre because of the technical challenges involved.

Women with Alport syndrome need additional clinical support during pregnancy and may need adjustments to their medication. Proteinuria can increase during pregnancy.

Genetic counselling, pre-implantation genetic testing and prenatal testing are options that can be discussed with your healthcare team, subject to local arrangements. This may involve testing embryos for Alport syndrome during a cycle of in vitro fertilisation (IVF) and only transferring unaffected embryos to the mother’s womb to ensure the birth of a child without the condition.

Various lifestyle adjustments may also be recommended to help maintain overall wellbeing. These include:

• Avoid smoking. Smoking damages the blood vessels in the kidneys and speeds up kidney damage.
• Eat a balanced diet. It is especially important to limit the amount of salt in the diet as too much salt can cause high blood pressure.
• Exercise regularly to help to control blood pressure.
• Avoid non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen (Nurofen®) as they can be very harmful to your kidneys.

Hearing aids may be prescribed to help with hearing loss, especially in school or college. Care should be taken around prolonged loud noises such as building sites or nightclubs, as this can further damage hearing. Headphone volume should also be controlled to avoid damage.

Children and teenagers may require support in school to help them cope with hearing loss and wearing hearing aids, as well as frequent absences for medical appointments.

Support may also be needed during transition to adult services. Kidney Care UK’s Young Adult Kidney Group (YAKG) is a closed support group specifically for kidney patients aged between 16 and 30. It provides a safe and inclusive environment for young adults living with CKD to chat, ask questions, learn from one another and share their thoughts and feelings with peers who they know will really understand, because they’re going through something similar.

Alport syndrome can eventually lead to kidney failure and the need for dialysis or a kidney transplant. People with Alport syndrome usually respond well to transplantation and the condition does not recur in the new kidney.

Where can I get more information or support about Alport syndrome?

For more information on Alport syndrome, including its genetics, diagnosis, symptoms and treatment, visit Alport UK, a patient-led organisation dedicated to empowering people living with Alport syndrome to enjoy the best possible quality of life.

There are currently a number of clinical trials taking place to research further treatment options for Alport syndrome. Talk to your kidney team for more information.

Publication date: 09/2026

Review date: 09/2029