Retinitis Punctata Albescens
Patient Information
Characteristics
Background and History
This disorder is often included in a group of rare hereditary disorders known as ‘flecked retina syndromes’. The designation is based on the presence of uniform small white or yellow lesions, usually dots, in the retina (the light sensing tissue lining the inside of the eye). Most have the common feature of nightblindness but retinitis punctata albescens also leads to loss of vision in daylight.
Clinical Correlations
The retina in this condition contains many symmetrically distributed white dots (sometimes called flecks) throughout the retina (the light sensing tissue lining the inside of the eye). These can be seen in the first decade of life and may be present at birth. Night blindness is a common complaint in children and vision is slightly decreased. With time, the flecks increase in number and are more widely distributed as the field of vision becomes increasingly constricted (limited side vision). As individuals age, the vision becomes worse and other changes such as pigmentation in the retina and constriction of blood vessels become evident.
There are no general health problems.
Genetics
Inheritance
This is an autosomal recessive condition requiring the presence of mutations in both copies of a gene. The parents, who carry one copy of the mutation, do not have symptoms but are sometimes found to also have some white dots in their retinas. Such parents can expect that each of their children carry a 25% risk of developing the symptoms of retinitis punctata albescens.
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 usually made by an ophthalmologist who may order an electroretinogram (ERG) and other tests to confirm the diagnosis. Low vision aids may be helpful in early stages of the disease but no other treatment is available. Longevity is normal.
Printer Friendly Version: Ctrl/Cmd+P