OMIM ID:
Retinitis Pigmentosa With or Without Skeletal Anomalies
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Downward slanting lid fissures may be detectable at birth as part of the general craniofacial dysmorphism. Some degree of night blindness causes symptoms by the second decade of life and constricted visual fields with pigmented retinopathy and vessel narrowing can be detected. The ERG shows reduced or absent responses. The retinal phenotype is progressive.
Systemic Features
Most but not all patients have skeletal anomalies. Nonspecific craniofacial dysmorphology features are frequently present including frontal bossing, macrocephaly, low-set ears, large columella, hypoplastic nares, and malar hypoplasia. A short neck, brachydactyly, and overall shortness of stature are often present. Some individuals have nail dysplasia. The proximal femoral metaphyses sometimes show chondrodysplasia.
There is often some degree of intellectual disability and there may be delays in speech, feeding, and walking.
Genetics
Inheritance
This disorder results from homozygous or compound heterozygous mutations in the CWC27 gene (5q12.3).
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.