Rare single-nucleotide variants (SNVs) have also been associated with autism, schizophrenia, and bipolar disorder. Unlike CNVs, SNVs require sequencing to be detected. Sequencing can be targeted to a specific gene, to all the coding portions of the genome (whole exome), or to the entire coding and non-coding parts of the genome (whole genome). These techniques have now become an important diagnostic tool in the evaluation of neurodevelopmental disorders, and they may eventually take the place of microarrays. Both CNVs and SNVs may be inherited from a parent or they may occur de novo (ie, not present in either parent).
