Jeans for Genes raises money for Genetic Disorders UK and aims to change the world for children with genetic disorders.
Individually, genetic disorders are rare but together they affect 1 in 25 children born in the UK - that's more than 30,000 babies each year. Their associated health problems mean that genetic disorders are the biggest cause of death of children aged 14 years and under.
The idea of Jeans for Genes Day originated in Dorset in the early 1990s. Two local brothers inspired a fundraising day that's now one of the best known - and loved - charity events in the UK.
The brothers had chronic granulomatus disorder (CGD), a life-threatening genetic disorder which affects the body's immune system.
The boys' family knew that The Chronic Glaucomatous Disorder Society wanted to support and care for children with the condition.