Deleterious, protein-altering variants in GSPT2 are putatively associated with an X-linked neurodevelopmental disorder with intellectual disability, language impairment, autism, and epilepsy.

Abstract

Approximately 6% of individuals with neurodevelopmental disorders are predicted to be X-linked, and the GSPT2 gene, located at Xp11.22, has not yet been associated with any Mendelian disease. To establish genotype-phenotype associations between GSPT2 and neurodevelopmental disorders, clinical investigations were performed in unrelated individuals, genomic and functional studies were conducted on the participants' blood and heterologous cell system. We described 6 individuals from 6 unrelated families carrying hemizygous variants in GSPT2 with intellectual disability, delayed speech and language development, autism spectrum disorder, epilepsy, or abnormal fetal neurodevelopment. Structural molecular modeling revealed significant deleterious effects of the identified variants. GSPT2 is preferentially enriched in the brain and cerebellum compared with other tissues. GSPT2-deficient H4 neuroglioma cells slow down the proliferation and downregulate the expression of cell-cycle-related genes. Transcriptomics revealed that GABAergic and calcium-signaling-related genes were significantly downregulated in GSPT2-deficient cells. Consistent with the transcriptomic data, RT-PCR analysis verified the marked downregulation of critical genes (CACNA1B, etc) in GSPT2-knockout cells and further confirmed these findings with proteomic profiling. Our data suggest a putative GSPT2-related X-linked neurodevelopmental disorders through dysregulation of cell-cycle progression and calcium/GABAergic signaling pathways.