De novo mutation in SLC25A22 gene: expansion of the clinical and electroencephalographic phenotype

Abstract

The SLC25A22 (Solute Carrier Family 25, Member 22) gene encodes for a mitochondrial glutamate/H⁺ symporter and is involved in the mitochondrial transport of metabolites across the mitochondrial membrane. We hereby report a 12-year-old girl presenting with early-onset epileptic encephalopathy, hypotonia, and global developmental delay. Whole exome sequencing identified a novel homozygous missense mutation in SLC25A22 gene (c.97A>G; p.Lys33Glu), as the likely cause of the disease. The phenotype of our patient and EEG recordings do not completely overlap with the phenotypes previously described, leading to a new and more complex form of disease associated with SLC25A22 variants, characterized by dyskinetic movements and oculogyric crisis.

Keywords:

• Dyskinetic movements
• epileptic encephalopathy
• glutamate
• oculogyric crisis
• SLC25A22 gene

Acknowledgements

We gratefully acknowledge the family for the enthusiastic collaboration to this study.

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This study was supported in part by The Wellcome Trust in equipment and strategic award (Synaptopathies) [WT093205 MA and WT104033AIA].