Potential Association of the CSMD1 Gene with Moderate Intellectual Disability, Anxiety Disorder, and Obsessive–Compulsive Personality Traits

<i>CSMD1</i> is a gene involved in various biological processes and is highly expressed in the central nervous system, where it plays a key role in complement activity, brain circuit development, and cognitive function. It has been implicated as a susceptibility gene for schizophrenia and a causative factor in developmental epileptic encephalopathy, neurodevelopmental disorders, and intellectual disability. However, no MIM phenotype number has been assigned to <i>CSMD1</i> for a specific disorder. Here, we report an individual presenting with moderate intellectual disability, anxiety disorder, obsessive-compulsive personality traits, and facial dysmorphisms. Trio-based whole-exome sequencing (WES) identified two heterozygous <i>CSMD1</i> variants, c.8095A>G and c.5315T>C, both classified as variants of uncertain significance (VUS) according to ACMG criteria. Computational analysis using the DOMINO tool supported an autosomal recessive inheritance model for <i>CSMD1</i>. This study contributes to the growing evidence linking <i>CSMD1</i> to neurodevelopmental phenotypes, highlighting the need for further investigations to clarify its pathogenic role.