Admin_NHT Staff asked 5 years ago Uner Tan syndrome is a condition in which the individual has quadrupedal locomotion, which basically means using both arms and legs to walk and move from one place to another. Such individuals also show signs of under-developed speech and mental retardation. It is an autosomal recessive disorder and is linked with offspring who come from inter-family reproductions. Mutations in the VLDLR gene, which is a very low-density lipoprotein receptor gene, and its subsequent deficiency during the development of the brain is the major cause for this disorder. These mutations result in the disruption of the bipedal locomotion and indicate the re-emergence of the quadrupedal locomotion to compensate for the inability to maintain an upright posture