The landscape for rare diseases in 2024

By definition, rare diseases affect a small number of individuals (fewer than 1 in 2000 people in any WHO region); yet, with more than 7000 types of rare disease in existence, the burden worldwide is not insignificant. To date, approximately 300 million people live with rare diseases. Such individuals are often a neglected and marginalised group, especially those in low-income and middle-income countries. Around 80% of rare diseases have a genetic cause, almost 70% of which present in childhood; about 95% lack approved treatments; the average time for an accurate diagnosis is 4·8 years; and about 30% of children with a rare disease die before age 5 years.