<prompt> All are true about subacute combined degeneration of spinal cord except :Due to deficiency of vitamin B12Posterior column involvementCoicospinal involvementAbsent deep tendon reflexes  <response>: Answer is D Absent deep tendon reflexes: Subacute Combined Degeneration Of Cord is a condition of the spinal cord characterized by demyelination of its neurons due to deficiency of Vit B12 which results in defective deficient myelination. Such demyelination occurs predominantly in - Posterior column of spinal cord - Pyramidal tract of spinal cord Subacute Combined Degeneration Of Cord is characterized by involvement of: Posterior column of lower cervical upper thoracic region This is where changes commence. Paraesthaesias, consisting of tingling numbness and that of pins needles Q Loss of vibration sense Q Position sense is involved to a lesser extent. Q Ataxic gait Lateral columns coicospinal tracts Their involvement follows the involvement of post columns. Motor defects such as weakness and spasticity Q Increased deep tendon reflexes, clonusQ Plantar extensor Q Spastic gait Note that gait is initially ataxic but later becomes both spastic and ataxic. Qat an early stage patellar achilles reflexes may be diminished, increased or absent. 