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Cataracts, Hearing Loss, and Neurodegeneration

Cataracts, Hearing Loss, and Neurodegeneration

Patient Information

Characteristics

Background and History

This recently reported disorder is one of several in which the body is unable to properly metabolize copper.  A number of properly functioning enzymes are necessary for the body to be able to use this essential element.

Clinical Correlations

The clinical picture is not yet well-defined.  The disorder results in severe developmental delay and early death.  Improper development of a brain structure (cerebellum) can be seen on MRI.  Infants are born with cataracts.  Hearing loss also seems to be a feature although more individuals need to be studied before we know the full range of clinical features.

Blood levels of copper and the protein that carries it are low.

Genetics

Inheritance

A mutation in a pair of genes is necessary before this disease develops.  It is thus an autosomal recessive disorder carried in single dose by healthy parents who have a 25% risk of transmitting this condition to each of their children.

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

This a condition which is lethal in children based on the single report available.  It requires a blood and gene test to diagnose.

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