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Clinical features of X linked juvenile retinoschisis associated with new mutations in the XLRS1 gene in Italian families

F Simonelli¹, G Cennamo¹, C Ziviello², F Testa¹, G de Crecchio³, A Nesti¹, M P Manitto⁴, A Ciccodicola⁵, S Banfi², R Brancato⁴ and E Rinaldi¹

¹ Department of Ophthalmology, Seconda Università di Napoli, Naples, Italy
² Telethon Institute of Genetics and Medicine (TIGEM), Italy
³ Department of Ophthalmology, Università Federico II, Italy
⁴ Department of Opthalmology, HSR Università di Milano, Italy
⁵ Institute of Genetics and Biophysics "A Buzzati-Traverso" (IGB), Italy

Correspondence to:
Correspondence to:
Francesca Simonelli, Piazza Leonardo, 14 Napoli, 80129, Italia;
franctes{at}tin.it

Aims: To describe the clinical phenotype of X linked juvenile retinoschisis in eight Italian families with six different mutations in the XLRS1 gene.

Methods: Complete ophthalmic examinations, electroretinography and A and B-scan standardised echography were performed in 18 affected males. The coding sequences of the XLRS1 gene were amplified by polymerase chain reaction and directly sequenced on an automated sequencer.

Results: Six different XLRS1 mutations were identified; two of these mutations Ile81Asn and the Trp122Cys, have not been previously described. The affected males showed an electronegative response to the standard white scotopic stimulus and a prolonged implicit time of the 30 Hz flicker. In the families with Trp112Cys and Trp122Cys mutations we observed a more severe retinoschisis (RS) clinical picture compared with the other genotypes.

Conclusion: The severe RS phenotypes associated with Trp112Cys and to Trp122Cys mutations suggest that these mutations determine a notable alteration in the function of the retinoschisin protein.

Keywords: Italian families; X linked juvenile retinoschisis; XLRS1 gene; mutations; phenotype

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