The girl, who was so fat she underwent liposuction at the age of six, had gained weight throughout her childhood despite repeated attempts at dieting. She reached 208lb - the size of a heavyweight boxer - but as soon as daily injections with the hormone began she started to lose weight. After a year of treatment she lost 36lb - more than two-and- a-half stone.
Doctors at Addenbrooke's Hospital in Cambridge, who treated the girl, say her experience could eventually lead scientists to a drug treatment for obesity. The girl, from a Pakistani family, was born with a congenital deficiency of the hormone leptin, which has been shown in earlier research on mice to play a key role in the development of obesity.
Her parents were unable to control her appetite when she was young and her weight rapidly increased, says a report on the case in the New England Journal of Medicine. By the age of six her legs were so fat she had difficulty walking. Once given regular injections of leptin, her appetite was reduced, she ate less at mealtimes,stopped craving snacks between meals and began losing 2lb to 4lb a month, virtually none of it muscle and all of it fat.