The Ulas

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of 19 is from rural southern

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

. Five of the family (except for another, who has died) walk on all fours with their feet and the palms of their

hand A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "h ...

s in what is called a "bear crawl". Their quadrupedal

gait Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency. Di ...

has never been reported in anatomically intact

adult An adult is a human or other animal that has reached full growth. In human context, the term ''adult'' has meanings associated with social and legal concepts. In contrast to a " minor", a legal adult is a person who has attained the age of major ...

humans. The gait is different from the knuckle-walking quadrupedal gait of

ape Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its siste ...

s. In 2006, the family was the subject of a documentary: '' The Family That Walks On All Fours''. The affected siblings have a form of non-progressive congenital cerebellar ataxia. The brain impairments include cerebellar hypoplasia, mild

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply t ...

and a reduced corpus callosum. They are also mildly

intellectually disabled Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation,Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signific ...

and have problems in balancing on two

legs A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element ...

. However, they do not show the poor coordination of

speech Speech is a human vocal communication using language. Each language uses Phonetics, phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if ...

, and

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

movements often found in

cerebellar ataxia Cerebellar ataxia is a form of ataxia originating in the cerebellum. Non-progressive congenital ataxia (NPCA) is a classical presentation of cerebral ataxias. Cerebellar ataxia can occur as a result of many diseases and may present with symptoms ...

. The four sisters can do

needlework Needlework is decorative sewing and textile arts handicrafts. Anything that uses a needle for construction can be called needlework. Needlework may include related textile crafts such as crochet, worked with a hook, or tatting, worked with a ...

. They all share a

recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

on chromosome 17p.

Sources

Üner Tan Uner Tan (''Turkish'': Üner Tan) (May 1, 1937 – February 6, 2022) was a Turkish neuroscientist and evolutionary biologist. He is best known for his discovery and study of the human quadrupedal condition he named the Uner Tan syndrome. He taught ...

Çukurova University Çukurova University ( tr, Çukurova Üniversitesi) is a public university in Adana, Turkey. The university has sixteen faculties, three colleges, seven vocational colleges, three institutes and twenty six research and application centers. ...

Medical School in Adana, Turkey, has said that they show characteristics of the

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

ancestors of ''

Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

'', before the move to bipedalism. He calls the process "backward evolution" and he named the condition

Uner Tan syndrome Uner Tan syndrome (UTS) is a syndrome that was discovered by the Turkish evolutionary biologist Üner Tan. People affected by UTS walk with a quadrupedal locomotion and often have severe learning disabilities. Tan postulated that this is an exampl ...

. However,

Nicholas Humphrey Nicholas Keynes Humphrey (born 27 March 1943) is an English neuropsychologist based in Cambridge, known for his work on evolution of primate intelligence and consciousness. He studied mountain gorillas with Dian Fossey in Rwanda; he was the fi ...

, John Skoyles, and

Roger Keynes Roger John Keynes FMedSci (; born 25 February 1951) is a British medical scientist. He is a Fellow of Trinity College, Cambridge, and a professor within the Department of Physiology, Development and Neuroscience. Keynes is the third of four son ...

have argued that their gait is due to two rare phenomena coming together. First, instead of initially crawling as

infants An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

on their

knees In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

, they started off

learning Learning is the process of acquiring new understanding, knowledge, behaviors, skills, value (personal and cultural), values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machine learning, machines ...

to move around with a "bear crawl" on their feet. Second, due to their

congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

brain impairment, they found balancing on two

difficult. Because of this, their

motor development A motor neuron (or motoneuron or efferent neuron) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly ...

was channeled into turning their bear crawl into a substitute for bipedality. Defne Aruoba is a Turkish psychologist who was involved with the care and research of the Ulas family. Because of her experience working with the Ulas family, she planned to establish the Ulas Foundation, which will bridge the gap between social inequalities and reach out to other individuals and families in need of rehabilitation.

Notes

{{reflist Congenital disorders Kurdish families Turkish people fr:Quadrupédie#Quadrupédie humaine

Sources

See also

Notes