A TEENAGER who suffers from an extremely rare condition means if he falls asleep unassisted - he dies.Liam Derbyshire was born with Ondine's Curse, officially known as Congenital Central Hypoventilation Syndrome, which causes respiratory arrest due to a patient's lungs not functioning when they are asleep. The condition, which affects less than 1500 worldwide, means the 17-year-old has to be plugged into a life support machine and watched by a carer every night to keep him alive. Doctors gave Liam just six weeks to live after birth, but later this year the young man from Gosport, South Hampshire, is turning 18 and has truly defied all odds.