Klippel-Feil syndrome (KFS) is a rare disorder that impacts your spinal bone growth. If you have KFS, you’ll have been born with at least two spinal bones in your neck fused together. This can result in a short neck, low hairline, limited mobility, headaches, and back pain. But you may not have every symptom.

KFS can happen on its own or alongside other genetic conditions. It’s congenital, meaning the disorder is present while you’re in the womb and at birth.

There’s no cure for KFS, and treatment consists of symptom management. Treatment plans depend on the severity of your symptoms, but these can include physical therapy, medications, or surgery.

We’ll overview what experts know so far about how and why KFS occurs, complications, and what treatment and management options currently exist.

What is the life expectancy for people with Klippel-Feil syndrome?

Many people with mild KFS have a normal life expectancy. However, KFS is associated with congenital heart disease, which affects around 4 to 14 percent of those with the condition, and other disorders that could potentially impact life expectancy.

Was this helpful?

In KFS, your cervical (neck) vertebrae don’t develop properly during the early weeks of fetal development, causing congenital fusion. Scientists are still investigating why this occurs, as the exact cause of KFS is unknown. But researchers believe that KFS is likely caused by a combination of genetic and environmental factors.

KFS is tied to genes that are inherited, but most people don’t inherited it, meaning it doesn’t usually run in families. Pioneering research from 1997 estimated that KFS occurs in around 1 in 40,000 to 1 in 42,000 births.

When KFS is present in multiple people who are related, more recent research from 2013 and 2016 has linked its appearance to mutations in the following genes, among others:

  • Growth differentiation factor 6 (dominant)
  • Growth differentiation factor 3(dominant)
  • Mesenchyme homeobox 1 (recessive)
  • Ripply transcriptional repressor 2 (recessive)

When a gene is dominant, you can inherit it if only one of your parents has it. When a gene is recessive, both of your parents need to have it for you to inherit it.

All of the above genes play some role in the somite segmentation process. This means they’re involved in the development of vertebral bones in the spinal cord.

KFS is separated into types 1, 2, and 3, ranging from mildest to most severe. The way these types are defined has varied over the years, from the degree of vertebral fusion to the patterns of genetic inheritance.

If categorized by the extent of congenital fusion, the types can be organized like this:

  • Type 1: Single-level fusion of a cervical segment. This means fusion of one neck vertebrae to another.
  • Type 2: Multiple fusions of cervical segments. These are noncontiguous, meaning they aren’t next to each other.
  • Type 3: Multiple fusions of cervical segments. These are contiguous, meaning they’re next to each other.

Types 2 and 3 are associated with more limited mobility, spinal cord compression (myelopathy), and pinching of the spinal cord’s root nerve in your lower back (radiculopathy). This can cause pain, stiffness, weakness, and numbness in your limbs.

Associated conditions

KFS is associated with several co-occurring conditions. These include:

  • kidney disease
  • hearing issues
  • congenital heart disease
  • brainstem abnormalities
  • congenital cervical stenosis
  • atlantoaxial instability

The severity of KFS symptoms can vary. Some people with the disorder have very mild symptoms or even none at all. Others have severe symptoms that impact their quality of life.

The KFS classic symptom “triad” is classified as:

  • an abnormally short neck
  • restricted head and neck movement
  • a low hairline

In previous decades, doctors required all of these clinical signs to be present to diagnose KFS. This is no longer the case, and experts agree people with KFS can include only some of the triad among other signs.

According to the National Institutes of Health and the National Organization for Rare Disorders, clinical manifestations and symptoms of KFS can include among others:

  • scoliosis (your spine curves to either side)
  • high scapula (high shoulder blades)
  • spina bifida
  • cleft palate
  • heart defects
  • breathing problems
  • nerve damage and nerve pain in your head, neck, and back
  • joint pain
  • hearing impairment
  • abnormalities in your organ function or structure, including kidneys, heart, and reproductive organs
  • skeletal abnormalities and malformations in your face, including your ears, nose, jaw, and mouth

The treatment for KFS depends on the symptoms that you have. Your treatment plan might change over the years to address any new symptoms you have as they occur.

Possible treatments for KFS include:

  • Physical therapy: Can help strengthen the muscles around your spine and can relieve pain. A physical therapist can also recommend a neck brace, supportive pillows, and other noninvasive pain relief methods you can use at home.
  • Surgery: Can be used to correct instability or constriction in your spinal cord. The exact surgery depends on factors such as how many spinal bones are fused together and how the KFS has impacted the other bones in your spine, shoulders, and upper body. For instance, implanting rods can help stabilize your spine, while spinal fusion can help straighten your spine.
  • Medication: You might be recommended or prescribed medication to help manage your skeletal, muscle, or nerve pain due to KFS. This could include antidepressants, muscle relaxers, nonsteroidal anti-inflammatory drugs, or corticosteroids.

KFS is usually visible at birth. Confirming a diagnosis can be done with radiology, which includes an imaging test such as an X-ray or MRI. These types of imaging will picture your spinal bones clearly, so doctors can see if any are fused together in your neck or upper back.

If you don’t have any symptoms, KFS can sometimes be identified later in your life by chance during an X-ray or MRI you have done for an unrelated medical reason.

KFS is a congenital spinal disorder that impacts the bones in your neck. If you have KFS, you’ll have been born with at least two bones in your neck fused together. For some people, this doesn’t lead to any visible signs or any symptoms. For others, KFS can lead to a wide variety of lifelong symptoms, including limited mobility, nerve, joint and muscle pain, skeletal abnormalities, and more.

Treatment for KFS depends on the severity of your symptoms. Medication, physical therapy, and even surgery can help manage your pain and improve mobility.