Corneal Dystrophy, Lattice Type II
Patient Information
Characteristics
Background and History
This form of inherited corneal disease, first described in Finland, is unusual because it is also a systemic disease. Its impact on general health can be more devastating than the effects in the cornea (the clear windshield of the eye).
Clinical Correlations
Lattice corneal dystrophy type II is a progressive disease with onset usually in adulthood. The opacities in the cornea may cause some loss of vision in young adults which may lead to the diagnosis. However, this is a disease of the whole body as a material called amyloid gradually deposits throughout, including the heart, nerves, facial muscles, skin, kidneys, blood vessels, and other tissues of the eye. Deposits in the nerves can cause a neuropathy which impairs the function of nerves such as those of facial muscles and the brain. This can lead to difficulty in speech and facial expressions. In older individuals the lower lip may become prominent. The skin is often dry and itchy. The most serious threat to health can be failure of the kidneys.
The corneas progressively become cloudier and in older individuals this can significantly impair vision. Corneal transplantation can improve vision but, because the nerves of the cornea do not function normally, and tear gland function is impaired, there is a risk in the post-operative period that the cornea will become dry and develop ulcers.
Genetics
Inheritance
This is an autosomal recessive disorder which is passed directly from parent to 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.
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 disorder may initially be diagnosed by your eye doctor but generally, because of the involvement of other organs, it requires a team effort. There is no treatment for the gene mutation. Cloudy corneas that impair vision can be replaced by a transplant. Kidney and other disease throughout the body requires appropriate attention from specialists.
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