The Ulas family is just like any other family except one thing: Some of the children walk on all fours. They have a strange and rare genetic disorder that makes them very misunderstood by people in their community. Called cursed, they have been persecuted, taunted, and shunned. They live in a remote part of Turkey and avoid going into the big city where they are not accepted. The family is large, with 12 normal children, and five that walk on all fours, one son and four daughters. The parents are normal and concerned for the wellbeing of their children when they pass away.

When scientists first discovered the family in 2005, there was a huge debate on whether they were a product of reverse evolution. Uner Tan, a Turkish evolutionary biologist was the first to spark the conversation. When he studied the Ulas family, he concluded they had a condition he called the Uner Tan syndrome, a condition that severely damages the brain.

The syndrome is known to cause mental retardation and a lack of coordination and balance, which causes the Ulas family to have their quadrupedal gait. Tan believed these unique children were proof of reverse evolution, meaning their genes traced back to their early ancestors who walked like apes. The idea of reverse evolution was just a flash, an ‘Aha’ experience,” Tan told NeuroQuantology. “I suddenly realized they were exhibiting the walking style of our ape-like ancestors...I was the scientist who first suggested the existence of reverse evolution in human beings.”

Not everyone agrees with Tan’s theory. Liza Shapiro and her colleagues recently spoke out about their research.  Disproving Tan’s hypothesis, they say research proves that the Ulas children walk on fours as an adaptation to their genetic condition. Early primates walked in a different diagonal pattern, they say in their research. Their conclusion: “In fact, the quadrupedalism exhibited by individuals with UTS resembles that of healthy adult humans asked to walk quadrupedally in an experimental setting. We conclude that quadrupedalism in healthy adults or those with a physical disability can be explained using biomechanical principles rather than evolutionary assumptions,” the study said.

The Ulas are not the people struggling with this disease; there are more, and most of them from Turkey. According to research by the Open Neurology Journal, in 2005 there were 14 reported cases of Uner Tan syndrome, all in Turkey. A 12-year-old boy developed quadrupedalism when he was 10 and walked on all fours to move quickly.  He never was able to speak. What is causing this disease? Scientists noticed a trend with many cases: The children’s parents share the same blood.  In the Arab culture it is common to marry in your bloodline.  It’s called consanguinity (shared blood).  Consanguinity makes you more prone to genetic disorders.  In the Ulas family, the parents are cousins. 

Currently scientists don’t offer a cure for Uner Tan syndrome but the Ulas children received hope that they may be able to walk one day. Doctors gave them walkers to help with coordination and balance. They also had bars put outside of their home so they can exercise their upper and lower bodies. At the end of the documentary, one of the sons, Hussein, was able to walk a few steps.

Source:Source: Shapiro LJ, Cole WG, Young JW, et al. (2014) Human Quadrupeds, Primate Quadrupedalism, and Uner Tan Syndrome. PLoS ONE. 2014.