The severity of SLC1A2-associated neurodevelopmental disorders correlates with transporter dysfunction

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Excitatory amino acid transporter 2 (EAAT2) is crucial for glutamate transport and neurotransmission in the human brain.
• Neurodevelopmental impairments are associated with variations in the SLC1A2 gene, which encodes EAAT2.
• Understanding the functional impact of these variants is key to comprehending disease mechanisms.

Purpose of the Study:

• To investigate the functional consequences of 13 different SLC1A2 variants on EAAT2.
• To correlate molecular phenotypes of EAAT2 variants with clinical presentations in affected individuals.
• To establish a basis for predicting disease severity and tailoring personalized treatments.

Main Methods:

• Expression and function of nine novel missense SLC1A2 variants in mammalian cells.
• Confocal microscopy, enzyme-linked immunosorbent assays, and [3H]-D-aspartate uptake assays.
• Electrophysiological recordings to assess anion channel properties.

Main Results:

• Ten of 13 SLC1A2 variants significantly altered EAAT2 expression or function.
• Variants were categorized into loss-of-function, mild gain-of-anion-channel function, or mixed loss-of-transport/gain-of-anion-channel function.
• Distinct molecular phenotypes correlated with specific clinical traits and disease severity.

Conclusions:

• Associations between EAAT2 variant function and clinical phenotypes provide insights for predicting SLC1A2-associated neurodevelopmental disorder progression.
• Understanding these genotype-phenotype correlations can guide personalized treatment strategies for affected individuals.