Neurological Complications in Inborn Errors of Immunity: A Scoping Review of Clinical Spectrum, Pathophysiological...

Inborn errors of immunity (IEIs) are traditionally viewed as monogenic disorders of the immune system, but mounting evidence indicates that they often have underappreciated impacts on the nervous system. We review the emerging intersection between IEIs and neurological diseases, spanning neurodevelopmental and neurodegenerative manifestations. We discuss how genetic overlaps between immunity and brain development-for example, defects in DNA repair, chromatin remodeling, or cytokine signaling-can lead to combined immunological and neurological phenotypes. Clinical data from patient cohorts highlight that a substantial subset of IEIs present with neurodevelopmental disorders (such as autism spectrum disorder, intellectual disability, or ADHD) and/or neurodegenerative diseases (such as progressive ataxia, motor regression, or cognitive decline). These comorbidities arise through diverse mechanisms, including direct roles of immune genes in neural development, the impact of chronic inflammation on the brain, and metabolic byproducts toxic to neural tissue. We illustrate these mechanisms with examples such as ataxia-telangiectasia (a DNA repair defect causing immunodeficiency and cerebellar degeneration) and DiGeorge syndrome (a developmental immunodeficiency often initially diagnosed as autism). The translational importance of these insights is profound-recognizing neurological involvement in IEIs can improve early diagnosis and multidisciplinary care, whereas a deeper understanding of immune-neural crosstalk opens avenues for novel therapies (such as targeted anti-inflammatory treatments or gene therapies that address both immune and neural dysfunction). By integrating immunology and neuroscience perspectives, this comprehensive review sheds light on the immune underpinnings of certain neurologic diseases and underscores the importance of collaborative management for patients at this complex interface.