This large study started in February 2004. We aim to collect new DNA from all 10,000 twins that have already enrolled with us. In addition we will collect serum and urine. We have already collected samples from over 1300 twins and hope to have collected all samples by early 2007. As well as collecting samples from twins at our research centre based at St Thomas' Hospital in London we are also seeing twins at a number of regional centres throughout the UK - Birmingham, Bristol, Nottingham, Aberdeen, Glasgow and Leeds. DNA will be stored in a way that will provide a perpetual source of material for researchers in the years to come. TwinsUK will be widely available to approved to genetic researchers from all branches of medicine and biology and the results will be well publicised both to the scientific community and to the public.