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Cataracts 45

Cataracts 45

Patient Information

Characteristics

Background and History

This is a recently described congenital cataract, one of many heritable types.

Clinical Correlations

This is an autosomal recessive condition caused by mutations in both members of a specific gene.  The parents, who carry a single copy of the gene change (mutation), are clinically normal with no evidence of cataracts.  However, such parents confer a risk of 25% of developing these cataracts to each child.

Genetics

Inheritance

This is an autosomal recessive condition caused by mutations in both members of a specific gene.  The parents, who carry a single copy of the gene change (mutation), are clinically normal with no evidence of cataracts.  However, such parents confer a risk of 25% of developing these cataracts to each child.

Pedigree

Autosomal recessive

In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent.  Carriers with only one mutation, such as the parents, do not have clinical disease.  Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.

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Sample pedigree of autosomal recessive inheritance

In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.

Diagnosis and Prognosis

An ophthalmologist can diagnose these cataracts with an eye examination.  They can be surgically removed but should be done as soon as diagnosed to lessen the risk of developing ‘lazy’ eyes (amblyopia).  Patients must be followed for the rest of their lives and corrective lenses used to provide full vision.

There are no associated physical or mental problems and longevity would be expected to be normal.

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