Molecular Screening Reveals De Novo Loss-of-Function NR4A2 Variants in Saudi Children with Autism Spectrum Disorders:...

Dysregulated expression of nuclear receptor superfamily 4 group A member 2 (NR4A2) has recently been associated with autistic spectrum disorder (ASD), speech impairment, and neurodevelopmental delay (NDD); however, its precise role in the prevalence and etiopathogenesis of ASD has not been fully elucidated. Herein, we aimed to explore the role of NR4A2 variants in the genetic underpinnings of ASD among Saudi children of different age ranges and phenotype severities. A total of 338 children with ASD from 315 unrelated families (293 simplex, 2 quads, and 1 quintet) were screened for NR4A2 variants via exome sequencing (ES) of the genomic DNA extracted from peripheral blood mononuclear cells (PBMCs), after which the probands with identified NR4A2 variants were further subjected to trio genetic analyses. ES analysis revealed 10 de novo NR4A2 variants (5 indels/nonsense, 2 missense, and 3 variants affecting splicing) in 8 unrelated probands (2.37%) and 2 affected siblings from 8 unrelated families (6 simplex (2.04%) and 2 quads (8.7%)). Three NR4A2 variants were notably recurrent among both affected and unaffected carriers. All identified indels and two splicing variants met the criteria for pathogenic/loss-of-function (LoF) variants according to the ACMG classification (PVS1), whereas the missense variants were classified as of uncertain significance (VUS). This study is among the first to identify such a high frequency of recurrent variants in an ASD cohort, suggesting their significant contribution to the etiopathogenesis of ASD within this population.