We expect that variants in the CHD3 gene to affect the ability of CHD3 proteins to regulate the expression of multiple other genes. The expression of genes depends on the accessibility of the gene, in other words, the accessibility of the DNA, and CHD3 moves histone proteins along DNA to make that regulatory DNA more, or less, accessible. We expect that some of the mechanisms involved in DNA accessibility during brain development are hampered in individuals with SNIBCPS. We want to study individuals that have variants in CHD3 for two reasons. First, we want to understand why variants in the same gene can cause a mild or a severe disorders. Second, we want to understand which genes in which brain regions are regulated by CHD3 during brain development to learn about more about the disease, but also more about brain development.