Technological advances have enabled genetic testing to become the first-line diagnostic investigation for individuals with early-onset epilepsies. A precise genetic diagnosis is essential because it has both personal and clinical utility and might enable timely administration of targeted treatments. Early genetic testing is, therefore, recommended in individuals with early-onset epilepsies, particularly developmental and epileptic encephalopathies.1 In The Lancet Neurology, Alissa D’Gama and colleagues2 investigate the outcomes of rapid genome sequencing in a prospective cohort of 100 infants with new-onset epilepsy, who were recruited from both inpatient and outpatient settings at four paediatric referral centres in Australia, Canada, the UK, and the USA.