Author opens dementia research

Pratchett has been diagnosed with early-onset Alzheimer's

Best-selling author Terry Pratchett is due to visit Bath later to open a new centre for research into Alzheimer's.

Pratchett, who has sold 55 million books worldwide, has PCA, a rare early-onset form of the disease.

He will cut the ribbon for The Research Institute for the Care of Older People at a ceremony at the Royal United Hospital.

The Wiltshire novelist has spoken out about his own battle with the disease and is campaigning for more research.

He was diagnosed with PCA, which affects the back of the brain and therefore vision and motor skills, in December 2007.

Pratchett, whose work has been translated into 27 languages, was given an OBE in 1998 for services to British literature.

His Discworld series is set in a parallel universe supported on the backs of four elephants that stand on the shell of a turtle.