Precision diagnostic and therapeutic interventions in rare genetic neurodevelopmental disorders

Neurodevelopmental disorders (NDDs) include a broad spectrum of phenotypes spanning from intellectual disability (ID) to developmental delay (DD) and autism spectrum disorder (ASD). As neurodevelopmental phenotypes are a common presenting feature of an underlying genetic condition, professional medical organizations recommend genetic testing for all individuals with a NDD. When testing is pursued, identified genetic differences can lead to personalized clinical management with early diagnosis supporting the development of surveillance and intervention for co-occurring adverse health outcomes. Despite this, barriers to testing have prevented individuals from receiving a genetics referral and testing. Current therapeutic modalities including small molecule drugs, gene therapies, and antisense oligonucleotide therapies have emerged and shown promise in preclinical trials with therapeutic drugs gaining FDA approval. However, translational challenges are extensive, especially for identifying biomarkers of drug effects in the CNS. In this review, we discuss diagnostic approaches and clinical utility of genetic testing for rare genetic neurodevelopmental disorders, emerging development of individualized therapies, and progress for current therapeutics in addition to challenges with clinical translation and delivery. We will highlight opportunities for early diagnosis and treatment that are steadily gaining ground in favor of optimizing long-term health outcomes and improving quality of life for neurodiverse individuals. IMPACT: The path from genomics to therapeutics for neurodevelopmental disorders continues to present multiple opportunities and challenges. While emerging genome-wide sequencing and gene editing technologies deliver increased diagnostic yields and alternatives to life-long small molecule therapies, clinical translation has been challenging due to inherent cost and genetic heterogeneity. Limited access to genetic testing despite practice guidelines remains a barrier towards precision therapeutics for rare neurodevelopmental disorders, while pre-clinical investigations face obstacles when translating to human subjects. This review will summarize the impact of existing successes in diagnosis and therapeutics for neurodevelopmental disorders while highlighting ongoing challenges and areas of future opportunities.