Kniest Dysplasia
Patient Information
Characteristics
Background and History
This disorder was first described by Dr. Wilhelm Kniest in 1952. It is a disorder of collagen, a complex molecule that is an important component of the connective tissue found throughout the body. This molecule is especially important to the structure and function of cartilage in joints.
Clinical Correlations
Kneist dysplasia has many features found throughout the body. The eye is larger than normal and this results in nearsightedness. The vitreous, the jelly-like material found in the back part of the eye, can deteriorate and this, with the enlargement of the eye, increases the risk of retinal detachments. The lens of the eye is sometimes displaced as the fibers that hold it in place are weak and defective. Cataracts also occur. Short stature with shortened arms and legs is common. The fingers are often long with knobby, stiff joints. Scoliosis and other abnormal curvature of the spine occur.
Genetics
Inheritance
This is an autosomal dominant disorder and can be inherited directly from an affected parent. Many cases, however, occur without a family history of the disease.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
Diagnosis and Prognosis
This is a complex disorder and one of several caused by mutations in the same gene. The diagnosis can be made by an eye doctor but generally a team of specialists is required to distinguish this disease from similar ones. The eye complications require careful monitoring for dislocated lenses and retinal detachments need to be treated promptly. The skeletal features and malformations can cause significant handicaps and need to be evaluated and treated by orthopedic surgeons.
Web Resources
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