Mutation Spectrum in the Rep-1 Gene of Japanese Choroideremia Patients
Background: Although the mutations of the REP-1 gene were reported in the Caucasian patients with choroideremia, no report was found in non-Caucasian patient except our previous case report. We performed multi-institutional study of the REP-1 gene in Japanese patients with choroideremia.
Methods: Twenty four unrelated Japanese families with choroideremia were analyzed. It included 24 patients and a carrier. The method for screening was a nonradioisotopic modification of single strand conformation polymorphism (SSCP). The PCR products from the patients and the carrier were screened and directly sequenced using an automated DNA sequencer.
Results: SSCP analysis showed abnormal band shifts in the patients and the carrier. Direct sequence analysis showed 15 kinds of mutations in 19 families. They included 8 nonsense mutations, 7 frameshift mutations, and 4 point mutations in the splice site.
Conclusion: The mutations in a racial background different from families reported before confirm that the REP-1 gene defect causes choroideremia. Most of Japanese patients with choroideremia are caused by the REP-1 gene mutations. No missense mutation has been found in Japanese patients either. Although large deletion was sometimes recognized in European patients, we could not find it in this series.
KeywordsJapanese Patient Nonsense Mutation Retinitis Pigmentosa Mutation Spectrum European Patient
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