OMIM ID:
Retinitis Pigmentosa 75
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Symptoms of night blindness and tunnel vision (restricted peripheral fields) are present in the first decade of life. The fundus appearance is typical for retinitis pigmentosa. Attenuated retinal vessels with a bone spicule pattern of pigment clumping are present. Evidence of optic atrophy with waxy pallor of the disc is usually visible. High myopia (>6 diopters) is frequently present.
Systemic Features
No systemic disease has been associated with this disorder.
Genetics
Inheritance
This condition generally follows an autosomal recessive inheritance pattern as the result of homozygous mutations in the AGBL5 gene (2p23).
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.