Retinal Nonattachment, Congenital
Patient Information
Characteristics
Background and History
The retina is the light-sensing tissue lining the inside of the eye. It is connected to the optic nerve by which the light-stimulated retina sends electrical signals to the brain enabling us to see. The retina must be attached to the eye to function properly and if it becomes detached, blindness results. This most commonly happens following trauma or when certain diseases such as diabetes cause damage. This type of detachment can often be repaired surgically.
Congenital nonattachment of the retina is present at birth. It is usually not possible to repair since there is often scarring and sometimes inflammation as well. It is frequently present unilaterally and the other eye may be normal. However, when it is bilateral it can follow familial patterns suggesting that it is inherited.
Clinical Correlations
Some light perception can be present at birth but in many children the disease is progressive and additional eye damage occurs. The jelly-like material (vitreous) that fills the posterior part of the eye is often scarred and contains some hemorrhage. Many patients have cataracts and clouding of the cornea (windshield of the eye) as well. The eye is often small and the pupil may appear white (leucocoria). Crossing of the eyes and to-and-fro movements are common. Glaucoma is sometimes present.
Individuals are otherwise healthy.
Genetics
Inheritance
This title as used here refers to a group of disorders in which the classification has not been defined. No specific gene mutation has been found but families have been reported with clear patterns of both autosomal dominant (vertical) and autosomal recessive inheritance. These are rare, though, and in most families it is not possible to calculate accurate risks of recurrence.
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
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.
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
Only an ophthalmologist can detect and diagnose detachment of the retina. A white pupillary reflex can, however, alert pediatricians and other physicians to an abnormality inside the eye which may be a detached retina among other things such as a cataract or a tumor. It is important in such cases to do a complete medical evaluation to look for other disease that suggests a more general syndrome.
Congenital nonattachment of the retina as described here occurs by itself. Most surgical attempts to reattach the retina in this condition fail and unfortunately, most such eyes eventually no longer respond to light.
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