Novel rhodopsin mutations and genotype-phenotype correlation in patients with autosomal dominant retinitis pigmentosa.
OBJECTIVE
To identify novel or rare rhodopsin gene mutations in patients with autosomal dominant retinitis pigmentosa and description of their clinical phenotype.


METHODS
The complete rhodopsin gene was screened for mutations by DNA sequencing in index patients. Mutation specific assays were used for segregation analysis and screening for controls. Eight patients from five families and their relatives were diagnosed with autosomal dominant retinitis pigmentosa (adRP) by means of clinical evaluation.


RESULTS
Mutation screening identified five different rhodopsin mutations including three novel mutations: Ser176Phe, Arg314fs16, and Val20Gly and two missense mutations, Pro215Leu and Thr289Pro, that were only reported once in a mutation report. Electrophysiological and psychophysical testings provide evidence of an impaired rod system with additionally affected cone system in subjects from each genotype group. Visual function tended to be less affected in subjects with the Arg314fs16 and Val20Gly mutations than in the Ser176Phe phenotype. In contrast, Pro215Leu and Thr289Pro mutations caused a remarkably severe phenotype.


CONCLUSIONS
The ophthalmic findings support a correlation between disease expression and structural alteration: (1) extracellular/intradiscal Val20Gly and cytoplasmic Arg314fs16 mutation-mild adRP phenotype; (2) Ser176Phe mutation-"mostly type 1" disease; (3) predicted alteration of transmembrane domains TM V and TM VII induced by Pro215Leu and Thr289Pro-severe phenotype. However, variation of phenotype expression in identical genotypes may still be a typical feature of RHO mutations.
Schuster
A
A
University Eye Hospital, Department of Neuroophthalmology, Schleichstr 12-16, D-72076 Tuebingen, Germany. andreas.schuster@med.uni-tuebingen.de
Weisschuh
N
N
Jägle
H
H
Besch
D
D
Janecke
A R
AR
Zierler
H
H
Tippmann
S
S
Zrenner
E
E
Wissinger
B
B
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000595:Amino Acid Sequence; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis / Q000379:methods; D005260:Female; D005799:Genes, Dominant; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D012174:Retinitis Pigmentosa / Q000235:genetics*; D012243:Rhodopsin / Q000235:genetics*; D014792:Visual Acuity; D014794:Visual Fields
D012243:Rhodopsin