Clinical Phenotypes Associated with NRXN1 Deletions in Five Children with Autism Spectrum Disorder in Oman.

NRXN1 (2p16.3) is essential for synaptic function and has been implicated in autism spectrum disorder (ASD) and other neurodevelopmental disorders. However, the phenotypic features associated with NRXN1 copy number variants remains incompletely characterised, which complicates risk assessment in genetic counselling. This case series describes five children, who were evaluated at the Genetics and Developmental Pediatrics Clinic of a tertiary care hospital in Muscat, Oman, from 2011 to 2023, with rare NRXN1 deletions (57-150 kb). All met DSM-5 criteria for ASD and had speech and language delays with cognitive impairment. Consanguinity was reported in three of the families and two had a family history of ASD. Microcephaly was present in four children and one showed facial dysmorphism. Generalised tonic-clonic seizures were present in one child and one child had comorbid attention deficit hyperactivity disorder. These findings illustrate clinical heterogeneity among children with NRXN1 deletions and supports the need for larger studies to better define genotype-phenotype relationships.