Background and objective: BRAT1 encephalopathy is an ultra-rare autosomal recessive neonatal encephalopathy. We delineate the neonatal electroclinical phenotype at presentation and provide insights for early diagnosis. Methods: Through a multinational collaborative, we studied a cohort of neonates with encephalopathy associated with bi-allelic pathogenic variants in BRAT1 for whom detailed clinical, neurophysiological, and neuroimaging information was available from the onset of symptoms. Neuropathological changes were also analyzed. Results: We included nineteen neonates. Most neonates were born at term (16/19) from non-consanguineous parents. 15/19 (79%) were admitted soon after birth to a neonatal ICU, exhibiting multifocal myoclonus, both spontaneous and exacerbated by stimulation. 7/19 (37%) had arthrogryposis at birth, and all except one progressively developed hypertonia in the first week of life. Multifocal myoclonus, which was present in all but one infant, was the most prominent manifestation, and did not show any EEG correlate in 16/19 (84%). vEEG at onset was unremarkable in 14/19 (74%) infants, and 6 (33%) had initially been misdiagnosed with hyperekplexia. Multifocal seizures were observed at a median age of 14 days (range: 1-29). During the first months of life, all infants developed progressive encephalopathy, acquired microcephaly, prolonged bouts of apnea, and bradycardia, leading to cardiac arrest and death at a median age of 3.5 months (range: 20 days to 30 months). Only seven infants (37%) received a definite diagnosis before death, at a median age of 34 days (range: 25 to 126), and almost two-thirds (12/19, 63%) were diagnosed 8 days to 12 years post mortem (median: 6.5 years). Neuropathology examination, performed in 3 patients, revealed severely delayed myelination and diffuse astrogliosis, sparing the upper cortical layers. Discussion: BRAT1 encephalopathy is a neonatal-onset, rapidly progressive neurological disorder. Neonates are often misdiagnosed as having hyperekplexia, and many die undiagnosed. The key phenotypic features are multifocal myoclonus, an organized EEG, progressive, persistent, and diffuse hypertonia, and an evolution into refractory multifocal seizures, prolonged bouts of apnea, bradycardia, and early death. Early recognition of BRAT1 encephalopathy allows for prompt workup, appropriate management, and genetic counselling.

Clinical and Neurophysiological Phenotypes in Neonates With BRAT1 Encephalopathy

Fedrigo, Marny;Angelini, Annalisa;
2023

Abstract

Background and objective: BRAT1 encephalopathy is an ultra-rare autosomal recessive neonatal encephalopathy. We delineate the neonatal electroclinical phenotype at presentation and provide insights for early diagnosis. Methods: Through a multinational collaborative, we studied a cohort of neonates with encephalopathy associated with bi-allelic pathogenic variants in BRAT1 for whom detailed clinical, neurophysiological, and neuroimaging information was available from the onset of symptoms. Neuropathological changes were also analyzed. Results: We included nineteen neonates. Most neonates were born at term (16/19) from non-consanguineous parents. 15/19 (79%) were admitted soon after birth to a neonatal ICU, exhibiting multifocal myoclonus, both spontaneous and exacerbated by stimulation. 7/19 (37%) had arthrogryposis at birth, and all except one progressively developed hypertonia in the first week of life. Multifocal myoclonus, which was present in all but one infant, was the most prominent manifestation, and did not show any EEG correlate in 16/19 (84%). vEEG at onset was unremarkable in 14/19 (74%) infants, and 6 (33%) had initially been misdiagnosed with hyperekplexia. Multifocal seizures were observed at a median age of 14 days (range: 1-29). During the first months of life, all infants developed progressive encephalopathy, acquired microcephaly, prolonged bouts of apnea, and bradycardia, leading to cardiac arrest and death at a median age of 3.5 months (range: 20 days to 30 months). Only seven infants (37%) received a definite diagnosis before death, at a median age of 34 days (range: 25 to 126), and almost two-thirds (12/19, 63%) were diagnosed 8 days to 12 years post mortem (median: 6.5 years). Neuropathology examination, performed in 3 patients, revealed severely delayed myelination and diffuse astrogliosis, sparing the upper cortical layers. Discussion: BRAT1 encephalopathy is a neonatal-onset, rapidly progressive neurological disorder. Neonates are often misdiagnosed as having hyperekplexia, and many die undiagnosed. The key phenotypic features are multifocal myoclonus, an organized EEG, progressive, persistent, and diffuse hypertonia, and an evolution into refractory multifocal seizures, prolonged bouts of apnea, bradycardia, and early death. Early recognition of BRAT1 encephalopathy allows for prompt workup, appropriate management, and genetic counselling.
2023
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3469921
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