Genetic condition to blame for family that walks on all fours, not 'devolution'

HATAY, Turkey, July 17 (UPI) -- In the tiny village of Hatay, Turkey, near the Syrian border, lives a family with five children that can't stand up. Up and down the stairs of the dusty stone buildings and along the villages dirt straights, they can can be seen walking on all fours, feet and hands on the ground, rump in the air. They -- unlike their 14 bipedal siblings and parents -- are physically incapable of any other method.

Their existence and their rare condition was shared with the world in a 2005 BBC documentary. Since then, there's been much conjecture among the scientific community over the reason for their four-limbed crawl of a walk. Some have suggested their constraint was an example of "devolution," a step backwards towards our quadrupedal days.

But a new study offers a more plausible (and it must be said, less offensive) explanation.

Not long after the documentary researchers suggested the five Turkish villagers relegated to all fours had a genetic condition known as Üner Tan Syndrome (UTC). The condition -- characterized by the tendency towards a quadrupedal gait, as well as balance and coordination problems and cognitive impairment -- was identified in other Turkish families. But this research was still viewed through an evolutionary lens, with some suggesting the genetic condition was the expression of some latent primal instinct.

However, a new study by Liza J. Shapiro, an anthropologist at the University of Texas at Austin, dispels such notions. The four-limbed walk is the product of the constraints brought about by the genetic condition, Shapiro says, nothing more.

She and her research colleagues compared the mechanics of the gait associated with Üner Tan Syndrome to the movements of various four-legged animals, including baboons and cats. They determined the UTC walk was dissimilar to any sort of animalistic walking technique.

"In fact, the quadrupedalism exhibited by individuals with UTS," the researcher explained in their study, "resembles that of healthy adult humans asked to walk quadrupedally in an experimental setting."

The new study was published this week in the journal PLOS ONE.