Screening for SLC7A14 gene mutations in patients with autosomal recessive or sporadic retinitis pigmentosa

ABSTRACT

Purpose: In this study, we aimed to detect mutations in the SLC7A14 cationic transporter gene, which has recently been reported as a causative gene for retinitis pigmentosa (RP), in Japanese patients with autosomal recessive (AR) or sporadic RP.

Materials and Methods: We included 146 unrelated Japanese patients with AR or sporadic RP who lacked mutations in genes known to be associated with RP despite next-generation sequencing-based screening. We sequenced the seven SLC7A14 coding exons along with their flanking intronic DNA using the Sanger method. The detected polymorphisms were assessed for their pathogenicity with in silico prediction tools. For those who had heterozygous, nonsynonymous variants, we performed multiplex ligation-dependent probe amplification (MLPA) to search for additional deletion/duplication.

Results: We detected four distinct SLC7A14 polymorphisms excluding synonymous polymorphisms. Two of these polymorphisms were assessed as detrimental by in silico prediction tools. However, all of the mutations were heterozygous. Neither homozygous polymorphisms nor compound heterozygous polymorphisms, which are considered detrimental variants, were detected. Neither deletion nor duplication was found with MLPA in patients with heterozygous variants.

Conclusions: The four SLC7A14 mutations detected herein were unlikely to be pathogenic in this Japanese cohort. The frequency and pathogenicity of SLC7A14 mutations may vary depending on ethnicity, and these mutations may be rare in Japanese patients.

KEYWORDS:

• MLPA
• retinitis pigmentosa
• Sanger sequencing
• SLC7A14

Acknowledgments

The authors would like to thank the Exome Aggregation Consortium and the groups that provided exome variant data for comparison. A full list of contributing groups can be found at http://exac.broadinstitute.org/about. The authors also thank Professor Fumihiko Matsuda for his technical advice and support.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This study was supported in part by the Japan Ministry of Health, Labor and Welfare (No. 12103069), JSPS KAKENHI (No. 26861445), and the Japanese Retinitis Pigmentosa Society. The funding organizations had no role in the design or execution of this research.

Additional information

Funding

This study was supported in part by the Japan Ministry of Health, Labor and Welfare (No. 12103069), JSPS KAKENHI (No. 26861445), and the Japanese Retinitis Pigmentosa Society. The funding organizations had no role in the design or execution of this research.