Sway back condition is seen due to deficiency of

A swayback condition is seen due to a deficiency of Cu.
Swayback is caused by copper deficiency during the prenatal/neonatal period. This condition is caused by bilateral, symmetric loss of myelin in the dorsolateral spinal cord tracts and the cerebral white matter.
It is a disease characterized by acquired copper deficiency which primarily manifests as myeloneuropathy.