Homozygous or compound heterozygous mutations in the BRAT1 gene have been described to cause lethal neonatal rigidity and multifocal seizures syndrome (RMFSL, OMIM #614498) leading to, among other, progressive postnatal microcephaly, muscular hypotonia, developmental delay, spasticity and rigidity, delayed myelination, degeneration of the basal ganglia, therapy-refractory epilepsy and in the end stage to a severe epileptic encephalopathy [18]. This evidence concerns the gene BRAT1 and neonatal-onset encephalopathy with rigidity and seizures.