Cataracts, Congenital, Autosomal Recessive 4
Patient Information
Characteristics
Background and History
Opacities in the normally clear lens of the eye are called cataracts. Most occurring in adults are age-related and little is known about their inheritance. Others, especially those in young people, are associated with heritable disorders of metabolism. The same is true of most cataracts at birth (congenital) or in infants and children. However, some lens opacities in youngsters such as those in the disorder described here, are found in isolation, that is without other more generalized disease.
Clinical Correlations
A single family with 4 affected offspring has been reported with this type of cataract. They were noted shortly after birth and had to be surgically removed. Two individuals developed glaucoma at the age of 7 and 8 years.
Genetics
Inheritance
This is an autosomal recessive condition that results from changes (mutations) in both copies of a specific gene. The parents and two additional children, who have no cataracts, carried only one copy of the mutation. The parents could expect that each of any additional children had a 25% risk of developing cataracts.
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 can be made by an ophthalmologist. No other sign of disease was present among those with cataracts. Surgical removal of the lens opacities may be required if they interfere with vision. Individuals with this type of cataract require lifelong monitoring and appropriate treatment for glaucoma if it occurs.
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