The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
|Signs and Symptoms||Approximate number of patients (when available)|
|Abnormal vertebral segmentation and fusion||90%|
|Cervical C2/C3 vertebral fusion||90%|
|Limited neck range of motion||90%|
|Low posterior hairline||90%|
|Vertebral segmentation defect||90%|
|Abnormality of the ribs||50%|
|Abnormality of the shoulder||50%|
|Congenital muscular torticollis||50%|
|Abnormality of limb bone morphology||7.5%|
|Abnormality of the cranial nerves||7.5%|
|Abnormality of the sacrum||7.5%|
|Posterior fossa cyst||7.5%|
|Ventricular septal defect||7.5%|
|Mixed hearing impairment||5/24|
|Unilateral renal agenesis||7/45|
|Abnormality of cardiovascular system morphology||21/505|
|Abnormality of the pinna||-|
|Autosomal dominant inheritance||-|
|Autosomal recessive inheritance||-|
|Cleft upper lip||-|
|Conductive hearing impairment||-|
|Fused cervical vertebrae||-|
|Sensorineural hearing impairment||-|
Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.
Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD. Suggest an organization to add.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
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My daughter was diagnosed with Chiari 1 malformation during childhood. Several years ago she was diagnosed with acute scoliosis and a fusion of 2 cervical vertebrae. Could it be possible that the Chiari is causing the scoliosis, even if there is no tethered cord or syringomyelia? Should she be checked for Klippel Feil syndrome? See answer
Is it possible for one identical twin to be born with Klippel Feil syndrome and not the other? See answer
Is there any relationship between Klippel Feil syndrome and low birth weight? See answer
As a young adult I was diagnosed with a fusion of C4 and C5. My question is whether this condition is automatically considered Klippel Feil Syndrome or whether there could be such a fusion without being diagnosed as KFS. See answer
Can Klippel Feil syndrome become life threatening? See answer
I am severely affected with Klippel Feil syndrome and my symptoms are worsening with time. Are there any research studies that I could participate in? I am also concerned about the risk to my future offspring. How can I learn more about this risk? See answer