OMIM ID:
Retinitis Pigmentosa 25
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
There is considerable clinical heterogeneity with a wide range in age of onset and progression. Night blindness, sometimes with photophobia, has its onset in the second or third decade of life and central acuity can be impacted by age 30 years. Other patients have no symptoms until the fifth decade. Some patients lose the ability to perceive light by the sixth decade. The visual fields are usually constricted although one patient had a central scotoma. The ERG is usually nonrecordable but other patients may have a variable rod-cone pattern of attenuation. The retinal vessels are also attenuated and some patients have mild optic atrophy. The pigmentary retinopathy is also variable with sometimes central lesions and in other patients more peripheral. One patient had posterior subcapsular cataracts.
Systemic Features
No systemic disease has been reported.
Genetics
Inheritance
This is an autosomal recessive form of retinitis pigmentosa resulting from homozygosity or compound heterozygosity in the EYS gene (6q12).
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.