Mild neurological phenotype in a family carrying a novel N-terminal null GRIN2A variant.

GRIN2A encodes for the 2A subunit of N-methyl-D-aspartate receptors. Pathogenic variants in GRIN2A have been associated with a wide spectrum of neurodevelopmental disorders ranging from speech disorders and/or self-limiting epilepsy (childhood epilepsy with centrotemporal spikes) to severe and disabling phenotypes (atypical childhood epilepsy with centrotemporal spikes, epileptic encephalopathy with continuous spike-wave during sleep, Landau-Kleffner syndrome and infantile-onset epileptic encephalopathy). Here we describe a family with two affected sisters with atypical childhood epilepsy with centrotemporal spikes and their mildly affected mother carrying a novel N-terminal null variant in GRIN2A gene. These familial cases corroborate previous studies showing that loss-of-function GRIN2A variants are associated with milder phenotypes, possibly due to haploinsufficiency.