1、RARE DISEASESImpact,landscape,and possibilitiesCAS INSIGHTSTMRare diseases,or orphan diseases,are a group of disorders that,despite affecting relatively few patients at the individual disease level,collectively affect many worldwide.The World Health Organization(WHO)defines a rare disease as one tha

2、t affects fewer than 65 per 100,000 people;1 however,when combined,would represent approximately 46%of the total worldwide population.13 Due to the rarity of the individual diseases,their complex presentation,and lack of clinician awareness,these conditions are often misdiagnosed or underdiagnosed.4

3、,5 Rare disease treatment and research,such as clinical trial recruitment,is further complicated by small patient populations and underfunding,and as a result,research does not advance as quickly relative to common diseases.1 The term“orphan disease”stems from this unmet need and the perception that

4、 rare diseases have been left“orphaned”by the pharmaceutical industry,with access to specialized healthcare and support made difficult for people living with such conditions.In recent years,awareness of rare diseases has grown,and there have been increased efforts in research to address unmet needs

5、in the field.Most rare diseases are genetic in etiology;consequently,research to identify genetic variants should provide the first steps toward a better understanding of the causes of these conditions.For example,advances in genomic sequencing and precision medicine could improve the diagnosis and

6、targeted treatment of patients with rare diseases.Initiatives and incentives such as the orphan drug legislation have also encouraged pharmaceutical companies to invest more resources in rare disease research.611 This is important because research investment in rare diseases can have positive impact