S14. PURA (Purine-Rich Element Binding Protein A) syndrome

Abstract

Introduction Burst suppression is an electroencephalographic (EEG) pattern characterized by a brief interval of relatively high voltage activity with intervening periods of generalized suppression. It is commonly seen consequent to anoxic brain injury, deep coma states, encephalopathies or hypothermia. This pattern is differentiated from trace discontinua because of longer interburst interval and higher amplitude during bursts. Myotonic discharges (M.D.) seen in an electromyographic (EMG) study are the abnormal wave of excitation due to the firing of repetitive action potentials. It is characterized by waveforms with alternating frequency and amplitude. This unique pattern is seen in muscular dystrophies, muscle channelopathies, toxic or inflammatory myopathies. We report a case of PURA syndrome with significant EEG findings of burst suppression and EMG pattern of myotonic discharges which has not been described in literature before. Methods A male infant was born at 37-week gestation via spontaneous vaginal delivery to a 35-year-old G1P0 after an uneventful pregnancy. At birth, the infant was observed to have generalized central hypotonia and seizure-like spells of posturing, lip-smacking and blinking lasting for 10–15 s. Family history was unremarkable. A video EEG and EMG were ordered for futher evaluation, in addition to other routine testing. Results Video EEG demonstrated excessive multifocal sharps and periods of burst suppression. EMG study reported myotonic discharges in the first dorsal interosseous and tibialis anterior. Work up for metabolic etiologies were negative. CSF studies, chromosomal studies, infantile epilepsy panel, myotonic dystrophy panel were unremarkable. Whole exome sequencing was significant for a de novo mono-allelic mutation of the PURA gene (variant PR245X, coding DNA c.733 C > T). Conclusion PURA (purine-rich element binding protein A) syndrome is a genetic disorder caused by a gene deletion in 5q31.3, characterized by neonatal hypotonia, seizures and intellectual disability. It leads to an alteration in the PURA protein, affecting the protein’s DNA regulatory function. All reported deletions have been de novo. Therefore the risk of future inheritance of this genetic mutation is low. PURA Syndrome is known to cause epilepsy in 54% of previously reported patients. In our case, the patient’s EEG pattern was consistent with burst suppression, which supports the fact that PURA Syndrome is a state of generalized brain dysfunction. EMG reports were consistent with myotonic discharges. The significance of this finding in our patient is unclear and requires further research to characterize EMG findings in affected patients with PURA syndrome. This case however underscores the importance of considering PURA syndrome in the differential diagnosis of neonatal EEG findings of burst suppression pattern and EMG findings of myotonic discharge.