Retinitis Pigmentosa, RDH11 Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Night vision problems and cataracts may be noted late in the first decade of life. The fundus has changes typical of retinitis pigmentosa such as a salt-and-pepper retinopathy and narrowing of the arterioles with relative sparing of the fovea. Confluent bone-spicule pigmentation is present in the periphery. The optic nerve may have a pinkish waxy appearance. Best-corrected visual acuity early is in the 20/25-20/30 range early in life with progressive deterioration. Full field ERGs and visual fields are consistent with retinitis pigmentosa with the scotopic system more severely affected than the photopic.
Systemic Features
Developmental delays and cognitive deficits are apparent in early childhood. Diastema and malocclusion may be present. Short stature (5th percentile) is characteristic along with facial dysmorphology consisting of hypoplasia of the alae nasae, malar hypoplasia and slight up slanting of the palpebral fissures.
Genetics
Inheritance
A single family with three affected sibs (2 boys and one girl) has been reported. The parents were phenotypically normal consistent with autosomal recessive inheritance. Two variants in the RDH11 (14q24.1) gene were identified in the (compound heterozygous) siblings as responsible for a truncated, inactive enzyme.
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.