A novel mutation of the RP1 gene (Lys778ter) associated with autosomal dominant retinitis pigmentosa.
BACKGROUND
Besides the three known genes (RHO, RDS/Peripherin, NRL) involved in autosomal dominant retinitis pigmentosa (adRP), a fourth gene, RP1, has been recently identified. Initial reports suggest that mutations in the RP1 gene are the second most frequent cause of adRP. The clinical findings were described in a family with adRP and a novel mutation in the RP1 gene.


METHODS
Index patients from 15 independent families with adRP in which RHO mutations had been excluded in previous examinations were screened for mutations in the RP1 gene by means of direct DNA sequencing. Evaluation of the RP1 phenotype in patients included funduscopy, kinetic perimetry, dark adapted final threshold test, standard electroretinography and, in one case, multifocal electroretinography.


RESULTS
One novel nonsense mutation (Lys778ter) in one of these 15 patients was detected. Cosegregation of the mutation with the disease phenotype could be established in the index patient's family. The phenotype comprises variable expression of clinical disease probably including one case of incomplete penetrance, a onset of symptoms beginning in adulthood, and evidence of regionally varying retinal function loss.


CONCLUSIONS
The Lys778ter mutation localises inside the critical region harbouring all mutations described so far. The ophthalmic findings support previous observations that variation of disease expression appears as a typical feature of the RP1 phenotype.
Dietrich
K
K
Molekulargenetisches Labor, Universitäts-Augenklinik, Auf der Morgenstelle 15, 72076 Tübingen, Germany.
Jacobi
F K
FK
Tippmann
S
S
Schmid
R
R
Zrenner
E
E
Wissinger
B
B
Apfelstedt-Sylla
E
E
D000368:Aged; D018389:Codon, Nonsense / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004596:Electroretinography; D005136:Eye Proteins; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008869:Microtubule-Associated Proteins; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D012174:Retinitis Pigmentosa / Q000235:genetics* / Q000503:physiopathology; D015534:Trans-Activators / Q000235:genetics*; D014792:Visual Acuity
D018389:Codon, Nonsense; D004268:DNA-Binding Proteins; D005136:Eye Proteins; D008869:Microtubule-Associated Proteins; C120042:RP1 protein, human; D015534:Trans-Activators