Cataracts, Congenital, Autosomal Recessive 2
Patient Information
Characteristics
Background and History
Opacities of the lens in the eye (cataracts) can result from a variety of causes such as infections, trauma, and various systemic diseases. Some like this one are inherited as the result of a mutation in a gene.
Clinical Correlations
This type of cataract has been reported in a small number of inbred Pakistani and Arab families. The opacification of the lenses are located centrally in what is known as the nucleus and are sufficiently dense to interfere with vision from the onset. They may be present at birth or develop within a few months of life. No other eye problems or systemic disease are present.
Genetics
Inheritance
This is an autosomal recessive condition in which both copies of a gene have been changed (mutated). The parents apparently do not have cataracts but since they each carry one copy of the mutation, they can expect their future children to each have a 25% risk of having this type of cataract.
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 diagnosis is made by an eye doctor. If the cataracts interfere sufficiently with vision, surgery may be indicated. Longevity is likely not impacted and no other disease is present.
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