Fact or fiction

July 2005. Rural Turkey. Five members of the same family are found to suffer from a recessive gene disorder which has caused brain damage affecting balance and movement. Result: they walk on all fours - using their palms like heels, with their fingers angled up from the ground (as opposed to the knuckle walking more often associated with chimps and gorillas). Their 14 siblings are not affected by the disorder. The family are treated as outcasts by many villagers - but that may change after the BBC documentary about them screens next week.