BRAT1 and neonatal-onset encephalopathy with rigidity and seizures: Pathogenic variants in <i>BRAT1</i> are associated with a spectrum of clinical syndromes ranging from Lethal Neonatal Rigidity and Multifocal Seizure syndrome (RMFSL) to Neurodevelopmental Disorder with Cerebellar Atrophy and with or without Seizures (NEDCAS).