Klippel-Feil Syndrome (KFS)

What is Klippel-Feil syndrome (KFS)?

Klippel-Feil syndrome (KFS) is a rare skeletal disorder primarily characterized by an abnormal fusion of two or more bones of the spinal column (vertebrae) within the neck (cervical vertebrae). This vertebral fusion is present from birth.

There are three subtypes of KFS:

• Type I: Massive fusion of the cervical spine
• Type II: Fusion of one or two vertebrae
• Type III: Presence of thoracic and lumbar spine anomalies in association with type I or type II Klippel-Feil syndrome

What are the symptoms of Klippel-Feil syndrome?

Three major features result from this vertebral fusion: a short neck, the resulting appearance of a low hairline at the back of the head, and a limited range of motion in the neck. Most affected people have one or two of these characteristic features. Less than half of all individuals with KFS have all three classic features of this condition.

In some individuals, KFS can be associated with a variety of additional symptoms and physical abnormalities. These may include:

• Abnormal curvature of the spine (scoliosis) and/or vertebral instability
• Spina bifida occulta
• Raised scapula (Sprengel’s deformity)
• Absent rib(s) and other rib defects including cervical ribs
• Skeletal malformations of the ear, nose, mouth, and larynx, including hearing impairment
• Cleft palate
• Malformations of the head and facial (craniofacial) area
• Anomalies of the urinary tract and/or kidney including absent or horse-shoe kidney
• Structural abnormalities of the heart (congenital heart defects)
• Webbing of the fingers and/or toes
• Digital hypoplasia

What causes Klippel-Feil syndrome?

Generally, KFS appears to occur randomly and for unknown reasons. However, in other cases, familial patterns have been reported that indicate autosomal dominant or autosomal recessive inheritance. Most likely, KFS is multifactorial, which means that several different factors, including genetic factors, all play some causative role. In addition, different genetic defects can cause KFS (genetic herterogeneity) in different people. 

How is Klippel-Feil syndrome diagnosed?

KFS may be diagnosed at birth based on a thorough clinical evaluation, identification of characteristic physical findings, and specialized tests. An MRI is often used to confirm diagnosis.

Additional specialized tests may also be conducted to help detect and/or characterize other abnormalities that may be associated with KFS.

What treatments are available for Klippel-Feil syndrome?

The treatment of KFS is directed towards the specific symptoms and associated physical findings that are apparent in each individual.

Therapy for KFS can include a variety of conservative measures including the use of cervical collars, braces, traction, non-steroidal anti-inflammatory drugs (NSAIDs), and various pain medications.

Where can I find out more about Klippel-Feil syndrome (KFS)?

• NIH
• Medscape
• National Organization for Rare Disorders (NORD)

• Klippel-Feil Syndrome Freedom