BRAT1 Mutation Retrospective Diagnosis: A Case Report.

Biallelic mutations in the BRAT1 gene have been reported in cases with Lethal neonatal rigidity and multifocal seizure syndrome (RMFSL), since 2012. Clinical features include progressive encephalopathy, dysmorphic features, microcephaly, hypertonia, developmental delay, refractory epilepsy, episodic apnea, and bradycardia. More recently, biallelic BRAT1 mutations have been associated with a milder phenotype in patients with migrating focal seizures in the absence of rigidity or with nonprogressive congenital ataxia with or without epilepsy (NEDCAS). It has been proposed that the loss of function caused by BRAT1 mutations may decrease cell proliferation and migration and cause neuronal atrophy through impairment of mitochondrial homeostasis. We here report a female infant with a phenotype, electroencephalogram (EEG), and brain magnetic resonance imaging (MRI) consistent with RMFSL, whose diagnosis was indirectly formulated three years after death upon the identification in both parents of a known pathogenetic variant in the BRAT1 gene. Our report emphasizes the remarkable potential of novel genetic technologies for the diagnosis of past unsolved clinical cases.