Peripheral nerve involvement in classic homocystinuria: an unusual association.

Classic homocystinuria is one of the most common causes of hereditary hyperhomocysteinemia. It is an autosomal recessive and multisystemic disorder due to cystathionine β-synthase deficiency. We described a case of an 18-year-old Portuguese man with an ischaemic stroke, who was subsequently diagnosed with classic homocystinuria [Thr191Met (c.572C>T) CBS mutation] associated with a sensorimotor neuropathy. The patient had a good clinical and metabolic response to pyridoxine plus methionine-restricted diet after 12 months of treatment. Neurophysiological re-evaluation with nerve conduction studies disclosed an improvement on the peripheral nerve lesion. Central nervous system manifestations in classic homocystinuria have been well documented, but this is to the best of our knowledge the first report of an association with peripheral neuropathy, which improved after hyperhomocysteinemia treatment. 2016 BMJ Publishing Group Ltd.