Gene enrichment analysis of the 100,000 Genomes Project and gene matching constructed a large cohort of SPTAN1 patients wherein three subgroups were defined: developmental epileptic encephalopathy, milder phenotypes of developmental delay with or without seizures, and patients with pure or complex hereditary spastic paraplegia/hereditary ataxia [49]. The gene discussed is SPTAN1; the disease is developmental and epileptic encephalopathy.