Different amino acid substitutions at the same position in rhodopsin lead to distinct phenotypes

Neidhardt, John; Barthelmes, Daniel; Farahmand, Firouzeh; Fleischhauer, Johannes C; Berger, Wolfgang (2006). Different amino acid substitutions at the same position in rhodopsin lead to distinct phenotypes. Investigative ophthalmology & visual science, 47(4), pp. 1630-5. Hagerstown, Md.: Association for Research in Vision and Ophthalmology 10.1167/iovs.051317

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PURPOSE: Identification of a novel rhodopsin mutation in a family with retinitis pigmentosa and comparison of the clinical phenotype to a known mutation at the same amino acid position. METHODS: Screening for mutations in rhodopsin was performed in 78 patients with retinitis pigmentosa. All exons and flanking intronic regions were amplified by PCR, sequenced, and compared to the reference sequence derived from the National Center for Biotechnology Information (NCBI, Bethesda, MD) database. Patients were characterized clinically according to the results of best corrected visual acuity testing (BCVA), slit lamp examination (SLE), funduscopy, Goldmann perimetry (GP), dark adaptometry (DA), and electroretinography (ERG). Structural analyses of the rhodopsin protein were performed with the Swiss-Pdb Viewer program available on-line (http://www.expasy.org.spdvbv/ provided in the public domain by Swiss Institute of Bioinformatics, Geneva, Switzerland). RESULTS: A novel rhodopsin mutation (Gly90Val) was identified in a Swiss family of three generations. The pedigree indicated autosomal dominant inheritance. No additional mutation was found in this family in other autosomal dominant genes. The BCVA of affected family members ranged from 20/25 to 20/20. Fundus examination showed fine pigment mottling in patients of the third generation and well-defined bone spicules in patients of the second generation. GP showed concentric constriction. DA demonstrated monophasic cone adaptation only. ERG revealed severely reduced rod and cone signals. The clinical picture is compatible with retinitis pigmentosa. A previously reported amino acid substitution at the same position in rhodopsin leads to a phenotype resembling night blindness in mutation carriers, whereas patients reported in the current study showed the classic retinitis pigmentosa phenotype. The effect of different amino acid substitutions on the three-dimensional structure of rhodopsin was analyzed by homology modeling. Distinct distortions of position 90 (shifts in amino acids 112 and 113) and additional hydrogen bonds were found. CONCLUSIONS: Different amino acid substitutions at position 90 of rhodopsin can lead to night blindness or retinitis pigmentosa. The data suggest that the property of the substituted amino acid distinguishes between the phenotypes.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ophthalmology
UniBE Contributor:	Fleischhauer, Johannes M.C.
ISSN:	0146-0404
ISBN:	16565402
Publisher:	Association for Research in Vision and Ophthalmology
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:49
Last Modified:	05 Dec 2022 14:15
Publisher DOI:	10.1167/iovs.051317
PubMed ID:	16565402
Web of Science ID:	000236560800049
URI:	https://boris.unibe.ch/id/eprint/20446 (FactScience: 3744)