In Turkey, there's a family with an apparent genetic disorder that causes them to walk on all fours. Scientists have speculated that they're an example of "devolution" — a backwards step towards our quadrupedal past. A new paper challenges this assumption, offering a far more reasonable explanation.
This condition came to light in a 2005 BBC documentary titled "The Family That Walks On All Fours." The film explored the story of five individuals, four females and one male, of the Ulas family who were exhibiting a previously unreported quadruped walking style. The condition has since been documented in other Turkish families, leading to a proposed genetic condition known as Üner Tan Syndrome (named after its discoverer, a Turkish evolutionary biologist).