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IRD is a generic term for a series of inherited progressive diseases in which retinal dysfunction is caused by genetic mutations. Many IRD patients experience symptoms beginning at an early age, such as difficulty seeing in dim light or a narrowing of the visual field, with some cases leading to blindness. The severity and progression of symptoms for IRD vary depending on the causative gene. Identifying the causative gene can lead to the development of better treatment plans, low vision care⁴ plans, and genetic counseling,⁵ which can improve the QOL of patients and their families. Thus, the importance of diagnosis based on genetic testing has increased in the diagnosis of IRD. In Japan, guidelines for genetic testing in IRD have been developed by the Japanese Ophthalmological Society and the Japanese Retina and Vitreous Society.

In recent years, both in Japan and overseas, gene therapy⁶ has been under development to target some of the causative genes of IRD, which was previously considered untreatable. On June 26, 2023, Novartis Pharma K.K. received manufacturing and marketing approval in Japan for “Luxturna” (generic name: voretigene neparvovec)⁷ as a gene therapy for IRD due to mutations in both copies of the RPE65 gene.⁸

From September 2023, Riken Genesis will begin assay services of the System, with quality assurance that complies with international standards.

Sysmex will continue its effort to create high-value testing and diagnostic technologies that support optimal healthcare for individual patients so that they can have a better healthcare journey.¹¹

Overview of National Health Insurance (NHI) Coverage in Japan

NHI category	C2
NHI point	20,500 (effective August 30, 2023)

Terminology

1	Gene panel testing: A testing method for simultaneously detecting mutations of multiple related genes.
2	Inherited Retinal Dystrophy (IRD): A hereditary progressive disease, presumed to be caused by a gene mutation, and including Retinitis Pigmentosa (RP), macular dystrophy, and Usher syndrome, which are designated in Japan as intractable diseases. Several diseases that present similar symptoms are collectively referred to as IRD. The main symptoms include night blindness (difficulty seeing in dim light), tunnel vision (a narrowing field of vision), and progressive loss of vision, which can lead to complete blindness in severe cases. It is estimated that one out of every 4,000 to 8,000 people develops a RP, the most common IRD subtype.
3	Comprehensive genome profile: Information obtained by simultaneously analyzing mutations of multiple genes significant to diagnosis.
4	Low vision care: A generic term for support of those who experience any difficulties in their daily lives due to vision problems, and including a wide range of support types, from medical to educational, vocational, social, welfare, and psychological care.
5	Genetic counseling: According to the Japan Medical Association, genetic counseling is a process that helps people adapt to diseases involving genes based on an understanding of their medical, psychological, and familial implications. Such counseling is provided to promote informed choices (knowledge-based decision making), involving relevant risks and conditions.
6	Gene therapy: A treatment method for diseases caused by genes that are defective or do not function normally, in which therapeutic genes are introduced into patient cells (in vivo gene therapy), supplementing defective genes with normal genes and thereby achieving therapeutic effects.
7	Luxturna (generic name: voretigene neparvovec): This drug was approved in the US in December 2017 and in the EU in November 2018 as a gene therapy that compensates for the functional deficiency of the RPE65 gene, one of the causative genes for IRD. On June 26, 2023, Novartis Pharma K.K. obtained manufacturing and marketing approval in Japan as a gene therapy for IRD caused by mutations in both copies of the RPE65 gene. Its NHI price listing is effective August 30, 2023.
8	RPE65 gene: The RPE65 gene is one of the causative genes for IRD. RPE65 gene mutations are believed to cause visual impairment due to a lack of the RPE65 protein, which is necessary to maintain the visual cycle.
9	Reference: The list of major genes that can cause IRD published by the Japanese Retina and Vitreous Society https://www.jrvs.jp/guideline/index.html (Japanese only)
10	Expert panel: A committee at a medical institution that meets the requirements stipulated by relevant academic associations. It is composed of experts in multidisciplinary fields, including those involved in IRD (ophthalmologists), genetic medicine (clinical geneticists), and molecular genetics and genome medicine. Panel members discuss and make proposals concerning the significance of the results of gene panel test results, treatment methods, and low vision care policies.
11	Sysmex promotes the concept of a “healthcare journey.” We view the various healthcare-related events a person experiences throughout their lives (life stages), along with the corresponding processes these involve (such as treatment at healthcare institutions), as a “journey”. Through various collaborations, we aim to offer new value, to make each individual’s healthcare journey better, and to grow as an essential presence in society.
12	The System, comprising a reagents kit and an analysis program, is used in combination with the NGS product, MiSeqDx System (Medical device approval number in Japan: 13B1X10303000002), for which Illumina Inc. is responsible for manufacturing and marketing in Japan.