Ectopia Lentis et Pupillae
Patient Information
Characteristics
Background and History
The title of this disorder describes pupils and lenses that are dislocated meaning they are not in the usual positions. There are a number of inherited disorders that can cause one or both of these dislocations but most also involve other eye and systemic abnormalities.
Clinical Correlations
This is a disorder, limited to the eye, in which the various structures near the front of the eye do not develop normally. This includes the iris (the colored part of the eye), and the lens as well as tissues where the cornea meets the iris which are responsible for regulating the pressure inside the eye. The iris is thin and only lightly pigmented so that light sometimes shines through. The pupils are often, although not always, displaced and dilate poorly. The lens is also sometimes displaced and may form a cataract at a relatively young age, that is, before the age of 60 years or so when most form. The pupil and lens are often displaced in opposite directions. Vision is may be subnormal, in the range of 20/60 to 20/100, which makes reading and near vision difficult and of course, below the limits of eligibility for a driver’s license. Other anomalies where the iris is attached to the inside of the eye result in blockage of fluid exiting from the eye and this can lead to glaucoma. Retinal detachments may also occur.
Genetics
Inheritance
This can be called an autosomal recessive disorder based on the limited data available. Both parents would need to carry the causative gene but would not have the condition. Careful examination of relatives, however, has revealed subtle ocular changes that suggest this may be a variable condition in which the inheritance is more direct, i.e., an autosomal dominant pattern. Mutations in a gene have been identified in several Norwegian families with ectopia lentis et pupillae.
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.
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 displaced pupil may suggest this condition by simple inspection. However, only your eye doctor can make the diagnosis after a complete eye examination. It is also important to have a complete physical examination since other more generalized disorders can have some of the same signs. Because of the risk of glaucoma, it is important to have regular eye examinations throughout life to avoid this blinding disease. Cataracts may need to be removed and the proper glasses prescription is important to maintain the best vision.
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