|
HealthTales.com |
|
| Index of Diseases and Conditions: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
Kniest dysplasia is a disorder of bone growth. This condition is characterized by short stature (dwarfism), enlarged joints and other skeletal abnormalities, and problems with vision and hearing.
People with this condition have short stature from birth, with a short trunk and shortened limbs. Adult height ranges from 42 inches to 58 inches. Progressive joint enlargement and pain restrict movement of the joints, which limits activity and interferes with standing and walking. These joint problems can also lead to arthritis. Other skeletal features include abnormal spinal curvature (kyphoscoliosis and lumbar lordosis), severely flattened bones of the spine (platyspondyly), dumbbell-shaped bones in the arms and legs, long and knobby fingers, and occasionally a foot deformity called a clubfoot.
People with Kniest dysplasia have round, flat faces with prominent and widely set eyes. Some affected infants are born with an opening in the roof of the mouth called a cleft palate. Infants may also have breathing problems due to weakness of the windpipe. Severe nearsightedness (myopia) is common, as are other eye problems that can lead to blindness. Hearing loss resulting from recurrent ear infections is also possible.
This condition is uncommon; the exact incidence is unknown.
Mutations in the COL2A1 gene cause Kniest dysplasia.
Kniest dysplasia is one of a spectrum of skeletal disorders caused by mutations in the COL2A1 gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). It is essential for the normal development of bones and other tissues that form the body's supportive framework (connective tissues). Mutations in the COL2A1 gene interfere with the assembly of type II collagen molecules, which prevents bones and other connective tissues from developing properly.
Kniest dysplasia is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. This condition is usually caused by new mutations in the COL2A1 gene and occurs in people with no history of the disorder in their family.
SED/SMD/Kniest Support Group - Extensive resources for people living with syndromes in the spondyloepiphyseal dysplasia, spondylometaphyseal dysplasia, and Kniest syndrome family.