Cataracts, Congenital, Volkmann Type
Patient Information
Characteristics
Background and History
Opacities in the lens of the eye, called cataracts, are caused by a variety of factors including trauma, infections, and gene mutations. They are often part of a more generalized systemic disease but some occur in the absence of other disease. Some are caused by changes in genes and can therefore be inherited. The Volkmann type is named after a German who immigrated to Denmark and established a large family with many descendents who inherited these cataracts.
Clinical Correlations
This type of cataract is usually present at birth. The opacities may be visually insignificant and some patients are unaware of their presence early in life. However, they are progressive and virtually all patients require surgery to remove them before the third decade of life when the lenses become too cloudy for good vision. Most patients with this type have been found in Denmark.
Genetics
Inheritance
This type of congenital cataract is inherited in an autosomal dominant pattern. Individuals with these lens opacities, both male and female, can expect that half of their children on average will inherit them.
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
Cataracts are usually diagnosed by an eye doctor based on an eye examination. An ophthalmologist may suggest removal when vision becomes sufficiently cloudy. The prognosis is good.
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