Eleven-year follow-up of a Japanese retinitis pigmentosa patient with an HK1 gene mutation

Abstract

ABSTRACT Background: Retinitis pigmentosa (RP) is a heterogeneous group of disorders that have a high genotypic diversity. Therefore, it is difficult to presume the genotype and/or prognosis from the presented phenotype. Establishment of a viable method for prognostic prediction requires accumulation and aggregation of long-term, follow-up data for respective RP genotypes. In this report, we present the long-term follow-up data for a patient with autosomal dominant RP resulting from a mutation in the HK1 gene. Materials and methods: A Japanese patient suffering from RP that was followed-up at our hospital for 11 years consented to participate in this study. The patient’s medical and family histories were gathered through patient interviews and clinical data were collected from medical records. The patient’s genotype was investigated using whole exome sequencing (WES). Results: Although the fundus showed typical RP, the patient’s visual deterioration over the 11-year follow-up period was limited. WES revealed a heterozygous, nonsynonymous variant in the HK1 gene (NM_000188: c. 2539G>A, p. E847K). This variant has previously been reported as a pathogenic variant of autosomal dominant RP. Autosomal dominant inheritance pattern was consistent with his family tree. Conclusions: We used WES to identify the first case of RP due to an HK1 gene mutation in Japanese patients and presented long-term, follow-up clinical data relating to the progression of the disorder. The detailed and long-term follow-up data for this genetically diagnosed RP patient are a valuable augmentation of existing knowledge and can help inform development of a prognostic prediction method for RP.