In our efforts to find the causes of the intellectual disability in our patients, we have come accoss novel novel syndromes and disorders. Starting from affected pedigrees, we elucidated for instance the causative genes in the MRX9 and MRXS10 families. Subsequently, we introduced MLPA as a screeinging tool for subtelomeric rearrangements. Using PamGene technology, we were able to implement array-based MLPA. Using this technology in combination with Illumina SNP arrays for copy number variation detection, we descibed the clinical consequences of the duplication of the Williams-Beuren syndrome region. Analysis of a balanced translocation led to the identification of the ANK3 gene as causative in neurodevelopmental disorders. The implementation of the Next Generation Sequencing technology allowed us to detect ADNP as one of the genes most frequently deleted in syndromic autism.