A random mutation in the gene can cause a person with no family history to also have the condition. Diagnostic techniques
A combination of medical tests are used to diagnosis Kniest dysplasia. These tests can include:
Computer Tomography Scan (CT scan) - This test uses multiple images taken at different angles to produce a cross-sectional image of the body. Magnetic Resonance Imaging (MRI) - This technique proves detailed images of the body by using magnetic fields and radio waves. EOS Imaging - EOS imaging provides information on how musculoskeletal system interacts with the joints. The 3D image is scanned while the patient is standing and allows the physician to view the natural, weight-bearing posture. X-rays - X-ray images will allow the physician to have a closer look on whether or not the bones are growing abnormally.The images taken will help to identify any bone anomalies. Two key features to look for in a patient with Kniest dysplasia is the presence of dumb-bell shaped femur bones and coronal clefts in the vertebrae. Other features to look for include:
Platyspondyly (flat vertebral bodies)
Kyphoscoliosis (abnormal rounding of the back and lateral curvature of the spine)
Abnormal growth of epiphyses, metaphyses, and diaphysis
Short tubular bones
Narrowed joint spacesGenetic Testing - A genetic sample may be taken in order to closely look at the patients DNA. Finding an error in the COL2A1 gene will help identify the condition as a type II chondroldysplasia. Treatment
Because Kniest dysplasia can affect various body systems, treatments can vary between non-surgical and surgical treatment.
Kniest dysplasia is a rare form of dwarfism caused by a mutation in the COL2A1 gene on chromosome 12. The COL2A1 gene is responsible for producing type II collagen. The mutation of COL2A1 gene leads to abnormal skeletal growth and problems with hearing and vision. What characterizes Kniest dysplasia from other type II osteochondrodysplasia is the level of severity and the dumb-bell shape of shortened long tubular bones.This condition was first described by Dr. Wilhelm Kniest in 1952, publishing the case history of a 3 1⁄2 year-old girl. Dr. Kniest noticed that his patient had bone deformities and restricted joint mobility. The patient also had short stature and later developed blindness, resulting from retinal detachment and glaucoma. Upon analysis of the patients DNA in 1992, sequencing revealed deletion of a 28 base pair sequence encompassing a splice site in exon 12 and a G to A transition in exon 50 of the COL2A1 gene.This condition is very rare and occurs less than 1 in 1,000,000 people. Males and females have equal chances of having this condition. Currently, there is no cure for Kniest dysplasia. Alternative names for Kniest Dysplasia can include Kniest syndrome, swiss cheese cartilage syndrome, Kniest chondrodystrophy, or metatrophic dwarfism type II. Signs and symptoms
Because collagen plays an important role in the development of the body, people with Kniest Dysplasia will typically have their first symptoms at birth.