<prompt> Vitamin B12 deficiency can lead to all EXCEPT:MyopathyPeripheral neuropathyOptic atrophyMyelopathy  <response>: Myelin formation requires B12 If B12 - myelination So, 1 Peripheral neuropathy 2 Optic atrophy 3 Myelopathy But Not Myopathy 4 SACD spinal cord Sub-acute combine degeneration of spinal cord 