Description
Kniest Dysplasia is a very rare condition that leads to short stature, malformed bones and joints, and sometimes vision and hearing problems. The condition was named after Dr. Wilhelm Kniest in 1952.
Kniest affects in 1,000,000 live births. The disorder affects males and females in equal numbers.
Symptoms
At birth:
- Short limbs, barrel-chest, eye problems, joints that do not extend all the way and may be swollen, decreased hearing, cleft palate, and a round mid-face with flat and round facial features.
- Other symptoms include a curved spine, instability of the cervical spine at C1 and C2 (vertebras in the neck), short neck, clubfoot, cleft palate, and poorly formed femur heads.
- Inguinal hernias may also be present.
- A distinctive feature is a ‘Swiss cheese’ pattern in cartilage observed in X-rays.
In children and adults:
- Spinal curvature may worsen over time.
- Joint contractures (inability to straighten) may get progressively worse, joints may get more swollen.
- Hearing and vision problems can also progress over time.
Note: A person may have some, but not necessarily all of the above symptoms.
Intelligence is usually unaffected.
Genetics
Kniest is a random genetic change. Kniest is usually sporadic and is due to the chance occurrence of a genetic mutation. It is the result of a genetic defect in encoding type II collagen (COL2A1). Most Kniest mutations are due to small changes on chromosome 12. Note that this is a purely random occurrence and that there is nothing either parent did to cause this genetic change.
Kniest has an autosomal dominant inheritance. When a person has Kniest, he/she has a 50% chance having a child with Kniest.
Is Intelligence affected?
People with Kniest usually have normal intelligence.
Expected Height
Height can vary. Usually about 100-140 CM or 39-55 in.
General Medical Care
Neck and vertebrae An evaluation of the C1 and C2 should be done to detect odontoid hypoplasia; spinal fusion may be indicated. Even though a spinal fusion may not be needed, lax ligaments in the neck could lead to spinal injury during anesthesia, contact sports, and car accidents. There also may be chest constriction, which can cause decreased lung capacity. Therefore, a person should be closely monitored during anesthesia and for complications during a respiratory infection.
Regular eye exams should be done by an ophthalmologist to evaluate for near-sightedness and detached retinas. A detached retina is an urgent condition. Any unusual eye symptoms should be reports to an ophthalmologist right away.
Hearing should be checked and ear infections should be closely monitored. Tubes may need to be placed in the ear.
During anesthesia, there are risks related to cervical spine instability, lung capacity, and small airways. Anesthesia should NOT be performed until these have been evaluated.
Orthopedic care may be needed to evaluate hip, spinal, and knee complications. Hip replacement is sometimes warranted in adults. Additionally, due to poorly developed type II collagen, people with Kniest may experience arthritis.
Always check with your medical doctor to evaluate your particular health care needs.
General Precautions
Due to neck instability, persons with Kniest should exercise caution to avoid activities/sports that could result in trauma to the neck or head.
More Information
KSG website can not keep track of the rapidly changing science! We suggest you visit the following sites for the most recent information:
LPA Medical resource center Kniest page: is an in-depth reference guide to the around 300 different types of dwarfism, intended not just for the lay person, but for medical professionals as well. The MRC also contains information about anesthesia, surgeries and procedures, common questions and a Frequently Asked Questions (FAQ).
Online Mendelian Inheritance in Man (OMIM) Kniest Page: MedlinePlus is an online health information resource for patients and their families and friends. It is a service of the National Library of Medicine (NLM), the world’s largest medical library, which is part of the National Institutes of Health (NIH).
Search https://medlineplus.gov/ . MedlinePlus is an online health information resource for patients and their families and friends. It is a service of the National Library of Medicine (NLM), the world’s largest medical library, which is part of the National Institutes of Health (NIH).
Recent Research
Search Pubmed for recent articles on Kniest Dysplasia. PubMed® comprises more than 36 million citations for biomedical literature from MEDLINE, life science journals, and online books.
