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A Rhodopsin Transport Assay by High-Content Imaging Analysis
Published on: January 16, 2019
CLRN1 mutations cause nonsyndromic retinitis pigmentosa
Muhammad Imran Khan1, Ferry F J Kersten, Maleeha Azam
1Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan.
Ophthalmology
|February 12, 2011
Summary
Mutations in the CLRN1 gene cause nonsyndromic autosomal recessive retinitis pigmentosa (arRP) in Pakistani families. These findings expand the known spectrum of CLRN1-associated retinal disorders beyond Usher syndrome type III.
Area of Science:
- Genetics
- Ophthalmology
- Molecular Biology
Background:
- Autosomal recessive retinitis pigmentosa (arRP) is a group of inherited retinal diseases.
- The CLRN1 gene is known to cause Usher syndrome type III (USH3).
- Consanguineous Pakistani families provide a valuable resource for studying rare genetic disorders.
Purpose of the Study:
- To identify mutations in the CLRN1 gene in two Pakistani families with arRP.
- To investigate the clinical and molecular characteristics of CLRN1-associated arRP.
- To differentiate CLRN1-related arRP from Usher syndrome.
Main Methods:
- Genome-wide linkage analysis using single-nucleotide polymorphism microarrays.
- Direct sequencing of the CLRN1 gene.
- Clinical examinations including fundoscopy, electroretinography (ERG), and audiometry.
- Subcellular localization studies of wild-type and mutant CLRN1 proteins.
Main Results:
- Two novel missense mutations, p.Pro31Leu and p.Leu154Trp, were identified in the CLRN1 gene.
- Patients exhibited retinal vessel attenuation, peripheral bone spicule pigmentation, and rod-cone dysfunction on ERG.
- No hearing impairment was detected, ruling out Usher syndrome.
- Mutant CLRN1 proteins were retained in the endoplasmic reticulum, unlike wild-type proteins at the cell membrane.
Conclusions:
- The identified CLRN1 mutations (p.Pro31Leu and p.Leu154Trp) are associated with nonsyndromic arRP.
- These mutations may be hypomorphic, leading to a milder phenotype than USH3.
- CLRN1 mutations are implicated in a broader range of retinal disorders than previously recognized.
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