Clinical and genetic findings of a Japanese patient with RP1-related autosomal recessive retinitis pigmentosa

Purpose This study reports the ophthalmic and genetic findings of a Japanese patient with autosomal recessive retinitis pigmentosa (arRP) caused by retinitis pigmentosa 1 (RP1) mutations. Patient and methods The 34-year-old female patient and her unaffected parents underwent comprehensive ophthalmic examinations, including visual acuity measurements, perimetry, electroretinography (ERG), and optical coherence tomography. Fundus autofluorescence was also evaluated in the patient. To identify potential pathogenic variants, 111 inherited eye disease genes were examined by targeted next-generation sequencing. Results The patient had night blindness from the first decade of her life. Fundus examination revealed typical RP findings with additional macular degeneration. Her visual field and acuity were severely affected, and ERG scans showed undetectable responses. Bioinformatics analysis revealed two heterozygous potentially pathogenic variants in RP1 in the patient, one of which is novel. Co-segregation analysis in the unaffected parents confirmed that the two variants were in trans. The parents were both carriers of one RP1 variant but did not show any visual symptoms. Therefore, the identified compound heterozygous variants were proposed as the probable arRP-causing mutations in the family. Conclusion This is the first description of a Japanese patient with arRP caused by RP1 mutations. Additional data are necessary to more accurately determine the clinical course and mutation spectrum in patients with RP1-related arRP.