Compound heterozygous BRAT1 mutations cause familial Ohtahara syndrome with hypertonia and microcephaly

Homozygous frameshift BRAT1 mutations were found in patients with lethal neonatal rigidity and multifocal seizure syndrome (MIM# 614498). Here, we report on two siblings with compound heterozygous mutations in BRAT1. They had intractable seizures from neonatal period, dysmorphic features and hypertonia. Progressive microcephaly was also observed. Initial electroencephalogram showed a suppression-burst pattern, leading to a diagnosis of Ohtahara syndrome. They both died from pneumonia at 1 year and 3 months, respectively. Whole-exome sequencing of one patient revealed a compound heterozygous BRAT1 mutations (c.176T > C (p.Leu59Pro) and c.962_963del (p.Leu321Profs*81)). We are unable to obtain DNA from another patient. The p.Leu59Pro mutation occurred at an evolutionarily conserved amino acid in a CIDE-N (N-terminal of an cell death-inducing DFF45-like effector) domain, which has a regulatory role in the DNA fragmentation pathway of apoptosis. Our results further support that mutations of BRAT1 could lead to epileptic encephalopathy.