Nail-Patella Syndrome

What is nail-patella syndrome?

Nail-patella syndrome is a genetic condition that affects your child’s nails, bones, eyes and kidneys. It changes how these parts look and/or function. Children with this condition commonly have underdeveloped fingernails and kneecaps (“patella” is the medical name for kneecap). These are the most obvious signs you can notice. But nail-patella syndrome can also cause changes that aren’t so easy to notice — like raised pressure in your child’s eyes or problems with kidney function.

Learning your child has a genetic condition may make you scared or anxious. This is normal, and it’s OK to express your concerns to your child’s healthcare providers. But take some comfort in knowing that providers can do a lot to treat symptoms and lower your child’s risk of complications. And most kids (and adults) with this syndrome have a normal lifespan.

What are the signs and symptoms of nail-patella syndrome?

Nail-patella syndrome can cause certain parts of your child’s body to look and/or function differently than expected. Here’s a breakdown of the most common signs and symptoms in different areas:

• Nails. Your child’s nails may be small or missing. They may have ridges, pits or discoloration. Fingernails are affected more often than toenails. Thumbs and index fingers usually have the most severe changes.
• Kneecap (patella). Your child’s kneecaps may be small, differently shaped or missing. They may be located higher up and farther to the side than usual. Your child’s knees might hurt, feel unstable or have a limited range of motion (how far they can move them). Patella dislocations are common.
• Elbow. Bones in your child’s arms may not develop as fully as expected. Your child may also have extra skin, called webbing, that extends across their elbow area. These changes might limit how well they can twist and extend their arms or flex their elbows.
• Pelvis. Your child may have tiny bony structures that extend from their pelvic bone. Providers call these iliac horns. There’s typically one on each side of your child’s pelvis. You may be able to feel them through your child’s skin, but they usually don’t cause issues.
• Eyes. Your child may develop increased pressure in their eyes (ocular hypertension), which can progress to glaucoma. There often aren’t any symptoms, but your child may notice mild headaches, “halos” around lights or blurry vision.
• Kidneys. About 4 in 10 people with nail-patella syndrome develop kidney disease either as a child or adult. It can range from mild to life-threatening. Mild kidney disease may gradually or suddenly become more severe.

Some people with nail-patella syndrome have other signs and symptoms, like:

• A tight Achilles tendon that leads to toe-walking
• Decreased muscle mass in their arms and legs
• Constipation and/or irritable bowel syndrome
• Decreased bone mineral density
• Tingling, burning or numbness in their hands and feet that occurs randomly
• Weak or crumbling teeth or thin enamel
• Abnormal curvature of their spine (scoliosis)

Researchers are working to better understand how common these issues are among people with nail-patella syndrome.

What causes nail-patella syndrome?

Changes to your child’s genes (gene variants) cause nail-patella syndrome. Most people with this syndrome have changes to their LMX1B gene. This gene tells your child’s body how to make a specific protein (LMX1B protein). This protein helps your child’s arms, legs, eyes and kidneys take shape during fetal development.

Gene variants cause the LMX1B protein to work differently than expected. As a result, various parts of your child’s body don’t form in typical ways, leading to the features of nail-patella syndrome.

Some people have the signs and symptoms of nail-patella syndrome without changes to their LMX1B gene. But this is rare. Researchers believe other genes might play a role, and they continue to look for more clues.

How is nail-patella syndrome inherited?

Nail-patella syndrome passes from one generation to the next in an autosomal dominant pattern. This means it takes just one copy of a gene variant — passed down from either biological parent — to cause the syndrome in a child.

If you have nail-patella syndrome, there’s a 50% chance that your biological children will be born with the condition. This risk stays the same for each pregnancy. It’s also the same no matter your sex.

About 9 in 10 people with nail-patella syndrome have a biological parent with the condition. But about 1 in 10 people appear to have no family history of it. This means some children are the first in their family to have this syndrome.

What are the possible complications?

Nail-patella syndrome may lead to:

• Osteoarthritis in your child’s kneecaps and/or elbows at an earlier age than expected
• Vision loss (if glaucoma isn’t treated)
• Kidney failure

Some people with nail-patella syndrome develop kidney failure that needs dialysis or transplantation.

Having nail-patella syndrome raises your risk of developing preeclampsia while pregnant. Providers monitor and adjust medications during pregnancy to help lower this risk.

How is nail-patella syndrome diagnosed?

Healthcare providers diagnose this condition by doing some or all of the following:

• A physical exam to look for features like nail changes and bone changes
• Imaging tests, like X-rays, CT scans and MRIs, to examine bones more closely
• Blood and/or pee (urine) tests to check kidney function
• A kidney biopsy to look for tissue changes typical of nail-patella syndrome
• Genetic testing to look for gene variants

Providers will talk to you to learn more about your child’s biological family history. For example, they’ll want to know if anyone has nail-patella syndrome or another genetic disorder. This information can help them reach a diagnosis. They may recommend genetic testing for you or other family members.

The features of nail-patella syndrome often appear early in life. But some people go years without a diagnosis due to mild symptoms or subtle signs. Providers diagnose this condition in children and adults of all ages.

Which providers will diagnose and treat my child?

Your child may need a team of several providers who are specialists in the areas of the body that nail-patella syndrome affects. For example:

• An orthopaedist will help with bone issues.
• A kidney doctor (nephrologist) will monitor your child’s kidney function.
• An eye care specialist will take care of your child’s eyes.

What is the treatment for nail-patella syndrome?

Nail-patella syndrome is something a person has for life. There’s no cure. But treatments can help manage symptoms and lower the risk of complications.

There are a wide range of options, and your child may need more than one treatment based on how the syndrome affects them. Your child’s providers will tailor treatments to their needs. What they might need can change over time, too. Possible treatments include:

• Physical therapy to help with movement
• Medications to manage musculoskeletal pain, blood pressure or pressure in their eyes 
• Surgery to manage bone abnormalities, glaucoma or severe kidney disease (including kidney transplantation)

Your child’s providers will explain the benefits and risks of each treatment. Managing a complex genetic syndrome in your child might feel overwhelming. Don’t hesitate to ask questions or share concerns so you can feel confident in your child’s treatment plan.

Can nail-patella syndrome be prevented?

There’s no known way to prevent this genetic disorder. If you or your partner have nail-patella syndrome and are thinking about having a baby, you may wish to speak with a genetic counselor. They can help you understand the chances of your baby inheriting this syndrome.

Does nail-patella syndrome affect life expectancy?

Nail-patella syndrome usually doesn’t affect a person’s life expectancy. The exception is if severe kidney disease develops. This complication can affect prognosis and how long a person lives. Some people need kidney transplantation.

Genetic disorders like nail-patella syndrome affect each child a little differently. And it’s hard to say exactly which features of this condition your child will have or how severe they’ll be. Your child’s healthcare providers can tell you more about what to expect.

When should my child see a healthcare provider?

Your child will likely need routine follow-ups with several different healthcare providers. Your child’s care team will tell you exactly which appointments are necessary and how often.

In general, your child may need routine:

• Blood pressure checks
• Pee (urine) tests, including those that measure albumin-creatinine levels
• Glaucoma screenings
• Bone density tests

Providers can help you explain the importance of these tests to your child.

It’s also important to pay attention to your child’s mental health — and to yours. Your child might feel self-conscious about their appearance or need help building up their confidence. You might wonder how best to be there for your child.

Talk to your child’s providers about connecting with support groups, therapists and social workers. Having a team of experienced parents and healthcare professionals supporting your family can make a huge difference from day to day.

How rare is nail-patella syndrome?

Researchers estimate that nail-patella syndrome affects 1 in every 50,000 people. But it might be more common because people with mild features go undiagnosed.

What is Fong’s disease?

Fong’s disease is another name for nail-patella syndrome. Providers mostly used it in the past. Today, most people use the term nail-patella syndrome.

Another name for this same condition is hereditary onycho-osteodysplasia. Here’s what each part of this name means:

• Hereditary means it can run in families.
• Onycho refers to nails.
• Osteo refers to bones.
• Dysplasia means a body part has abnormal growth or development.