What is Kniest Dysplasia?
Kniest Dysplasia is a very rare pathological condition of the musculoskeletal system in which there is abnormal bone growth which causes an individual to have an extremely short stature along with deformed bones and joints. There may also be other skeletal abnormalities as well. Kniest Dysplasia is so rare that it is estimated to occur in one among one million births. The classic presenting features of Kniest Dysplasia are distinct holes in the bone cartilage which can be clearly visualized on x-ray.
These small holes make the cartilage weak resulting in joint swelling and extreme stiffness of the joint. Babies born with Kniest Dysplasia have very short trunk and arms and legs. There may also be facial anomalies like a flat face or bulging eyes. Babies with Kniest Dysplasia also tend to have foot abnormalities as well. With time due to this condition, the affected child may require frequent visitation to the doctor for conditions like scoliosis, stiffness of the joint along with visual and hearing issues due to Kniest Dysplasia.
What Causes Kniest Dysplasia?
Kniest Dysplasia can be inherited as well as present as a new problem with spontaneous gene mutation. The gene responsible for causing Kniest Dysplasia is the COL2A1 gene. In some cases, the mutation of this gene occurs spontaneously and the baby may have this condition without any family history of this disorder whereas in some cases Kniest Dysplasia is inherited. Kniest Dysplasia is inherited in an autosomal dominant form meaning that only one copy of the defective gene from either parent is good enough to increase the risk of the child having Kniest Dysplasia.
What are the Symptoms of Kniest Dysplasia?
Some of the symptoms of Kniest Dysplasia are:
- Short stature with short limbs
- Short trunk of the body
- Hip dysplasia
- Stiffness of the joints
- Deformity of the joints preventing normal motion of the joints
- Extremely fragile bone cartilage
- Foot deformities
- Flat face with bulging eyes
- Cleft palate
- Hearing and vision problems
- Problems with breathing.
How is Kniest Dysplasia Diagnosed?
To diagnose Kniest Dysplasia, the doctor will first take a detailed history of the patient in order to figure out if there is a family history of a condition like Kniest Dysplasia. A physical examination will also be performed to look for any foot deformities, stiffness of the joints and also try to identify conditions like a cleft palate. Apart from this, radiological studies in the form of x-rays and CT or MRI scans of the bones will be done to look at the internal structures of the bones. The x-rays themselves will clearly show holes in the cartilage virtually confirming the diagnosis of Kniest Dysplasia.
If Kniest Dysplasia is suspected, then a genetic testing may be done to confirm the presence of mutation of the gene COL2A1 which will confirm the diagnosis of Kniest Dysplasia. If there is a family history of Kniest Dysplasia in any parent then a prenatal test can be done to check whether the child has this disorder or not by doing an ultrasound or amniocentesis which will clearly give an indication of whether the child has the gene mutations responsible for Kniest Dysplasia.
How is Kniest Dysplasia Treated?
Treating Kniest Dysplasia is quite complex because of the variety of disorders that are embedded in it apart from its own clinical presentation. Apart from the short stature, there are also orthopedic abnormalities like deformed limb, hip dysplasia, limb stiffness along with craniofacial anomalies like a flat face and thus treating Kniest Dysplasia requires a multidisciplinary effort. Surgeries will be required to treat conditions like limb length discrepancies, hip dysplasia and craniofacial anomalies where as extensive therapy may be needed to cope up with joint stiffness and difficulty with movement of the joints.
The timing of the surgery is something that needs to be planned. Some physicians prefer to wait till the child is a bit older to perform surgery but in majority of the cases the surgery is done when the child is young. Children with hearing and vision problems will be monitored closely to look for any worsening in the condition. Conditions like scoliosis and hip dysplasia become only evident when the child gets a bit old and hence surgery for treating these conditions is withheld until the symptoms become more apparent. Conservative treatments like use of a brace or a lift will also be done for limb stiffness and limb length discrepancies due to Kniest Dysplasia.
What is the Prognosis of Kniest Dysplasia?
Kniest Dysplasia does not affect the intelligence of a child and hence with treatment majority of the children with Kniest Dysplasia lead normal healthy lives, although there is a risk of the child developing early arthritis as a result of Kniest Dysplasia.