Subacute combined degeneration of the spinal cord (SCD) is the most frequent neurological manifestation of vitamin B₁₂deficiency. It is now seen much less often than in former years as the diagnosis is made earlier in most patients on haematological grounds. Nevertheless, patients in whom the initial manifestations are neurological still occur and it is a tragedy if early diagnosis is not made in this treatable condition. Presentation is either with a distally predominant sensory neuropathy, accompanied or preceded by myelopathy, and sometimes by optic atrophy or cognitive change. Suspicions that a sensory neuropathy may be related …