Blindness due to non-ketotic hyperglycinemia: report of a 38-year-old, the oldest case to date.

We report a 38-year-old woman with a mild form of hyperglycinemia complicated with optic nerve atrophy and convulsion. She was normal at birth and showed normal mental and physical development. After the age of 13, her visual acuity rapidly decreased. At the age of 33, she had numerous episodes of tonic seizures lasting for 1-2 minutes. She had optic atrophy, but no intellectual impairment. Glycine levels of the plasma, urine and cerebrospinal fluid were markedly increased, but the CSF/serum glycine ratio was slightly higher than the normal range. Although there is one case of retinal impairment of hyperglycinemia in the literature, this is the first report of blindness with hyperglycinemia in a 38-year-old woman.