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Microcornea, Myopia, Telecanthus and Posteriorly-Rotated Ears

Microcornea, Myopia, Telecanthus and Posteriorly-Rotated Ears

Patient Information

Characteristics

Background and History

This is an exceedingly rare disorder that has so far only been reported in 5 boys and a father.  The name is derived from the clinical abnormalities that are present.  

Clinical Correlations

Children from birth have very small corneas (the clear front of the eye) and the eye is longer than average resulting in nearsightedness.  The inside of the eye shows some degeneration in the retina characteristic of that seen in nearsightedness.  However, vision is reasonably good and there is no evidence of deterioration.  The inner corners of the eye are unusually far apart (telecanthus). 

The ears are rotated posteriorly.

 

Genetics

Inheritance

Nothing is known regarding the genetic cause of this condition.  All children were born into families where the parents were known or suspected of being related suggesting an autosomal recessive pattern of inheritance.

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

The diagnosis would be made by an ophthalmologist following a complete eye examination.  The prognosis for life is excellent although all reported patients were 10 or less years of age.  It would seem prudent to have periodic eye examinations throughout life as nearsightedness carries a risk for retinal degeneration and detachment.

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