Perspective on the paper by Bok et al ( see 687 ) Treatable metabolic causes of early onset epilepsy (in the first few months of life) are uncommon but it is important to diagnose them because delay in specific treatment commonly results in poor neurological and cognitive outcome. Indeed, some of these epilepsies are fatal if left untreated. The disorders are listed in table 1 and are divided into vitamin-responsive and other metabolic epilepsies. View this table: Table 1 Treatable metabolic causes of early onset epilepsy We are not going to discuss all of these disorders, but will confine ourselves to those presenting at or very close to birth. The investigation and treatment of the other epilepsies are summarised in table 2. View this table: Table 2 Investigation and treatment of metabolic causes of early onset epilepsy Typical neonatal onset pyridoxine-dependent epilepsy (PDE) presents in the first few days of life with multiple seizure types which are intractable to anticonvulsant drug treatment. Experienced mothers may also recognise seizures in utero from about 20 weeks of gestation. Approximately one third of infants with PDE will also have features of a neonatal encephalopathy (hyperalertness, irritability and a stimular sensitive startle) which can be accompanied by systemic features. Neuroimaging may show structural brain abnormalities, hydrocephalus or haemorrhage. EEG is abnormal but has no diagnostic features.1 The seizures and EEG abnormalities respond promptly (within minutes) to 100 mg of intravenous pyridoxine. However, in about 20% of infants with pyridoxine-dependent epilepsy the first dose of pyridoxine can also cause cerebral depression, which is more likely if the infant is receiving anticonvulsant drugs. Children with PDE require life-long treatment with pyridoxine at a dose of ∼15 mg/kg/day up to 500 mg/day. With prompt treatment prognosis is generally good, although there may be later learning difficulties, particularly with language. If …