The phenotype caused by recessive variations in SLC25A22: Report of a new case and literature review

We describe the clinical, electroencephalography (EEG), and developmental features of a patient with developmental and epileptic encephalopathy due to a homozygous pathogenic variation of mitochondrial glutamate/H+ symporter SLC25A22. Epilepsy began during the first week of life with focal onset seizures. Interictal EEG revealed a suppression-burst pattern with extensive periods of non-activity. The prospective follow-up confirmed developmental encephalopathy as well as ongoing active epilepsy and almost no sign of development at 8 years of age. We confirm in the following paper that SLC25A22 recessive variations may cause a severe developmental and epileptic encephalopathy characterized by a suppression-burst pattern. On the basis of an in-depth literature review, we also provide an overview of this rare genetic cause of neonatal onset epilepsy. (C) 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Automated summary

We present the case of a patient with developmental and epileptic encephalopathy due to a homozygous pathogenic variant of mitochondrial glutamate/H+ symporter SLC25A22. The patient started experiencing focal onset seizures in the first week of life, with interictal EEG showing a suppression-burst pattern. Long-term follow-up revealed ongoing active epilepsy and almost no developmental progress by 8 years of age, confirming the severe consequences of SLC25A22 recessive variations. This study provides insight into a rare genetic cause of neonatal onset epilepsy.