Over 50% of pediatric neurological and neurodevelopmental disorders lack a molecular diagnosis after standard DNA sequencing and molecular karyotyping. This is due to technical limitations, incomplete variant interpretation, and inadequate genotype-phenotype correlations. New sequencing technologies are crucial for clinical decision-making, offering complete profiles of variants in a patient's DNA to personalize treatment. Optical Genome Mapping (OGM) can detect nearly all structural variants in one experiment. This project aims to use OGM alongside NGS to improve diagnostic yield in 60 children with severe disorders who tested negative for NGS/CMA.