GRIN2A mutations in epilepsy-aphasia spectrum disorders

Area of Science:

• Neurogenetics
• Epilepsy Syndromes
• Molecular Biology

Background:

• Epilepsy-aphasia spectrum (EAS) disorders link epilepsy, speech impairment, and specific EEG patterns.
• Mutations in the GRIN2A gene, encoding an NMDA receptor subunit, have been associated with focal epilepsy and speech issues.

Purpose of the Study:

• To investigate the role of GRIN2A gene mutations in Chinese patients diagnosed with centrotemporal spike-related epileptic syndromes.
• To determine the frequency of GRIN2A mutations in specific EAS subtypes.

Main Methods:

• Recruited patients with Landau-Kleffner syndrome (LKS), epileptic encephalopathy with continuous spike-and-wave during sleep (ECSWS), atypical benign partial epilepsy (ABPE), and benign epilepsy with centrotemporal spikes (BECTS).
• Conducted GRIN2A mutation screening using polymerase chain reaction (PCR) and Sanger sequencing.

Main Results:

• Of 122 patients, GRIN2A mutations were found in 11.1% of LKS cases and 7.1% of ABPE cases.
• No GRIN2A mutations were detected in ECSWS or BECTS cohorts.
• Mutations were identified in four patients: G760S, D1385Y, C455Y, and C231R.

Conclusions:

• GRIN2A mutations represent a genetic cause in a minority (less than 11%) of LKS and ABPE patients.
• The GRIN2A gene is infrequently implicated in the pathogenesis of EAS in the studied Chinese cohort.
• Other genetic factors are likely involved in the development of these epilepsy syndromes.