Exome is the term used to refer to all the exons in the genome collectively. These are the DNA sequences that code for proteins, and are thus the functional part of the genome. They are the sequences that determine an organism’s phenotype1.
Mutations in the DNA sequence of the exome that inactivate genes can often lead to various disorders. Recent advances in DNA sequencing technology are enabling researchers to interrogate the entire sequence of the exome at once in order to identify disease-causing mutations.
Exome sequencing has been applied to uncover mutations responsible for several Mendelian disorders2,3, including cases of severe brain malformations4.
Relevance to autism:
Whole-exome sequencing is expected to be particularly useful in uncovering mutations that cause autism.
Due to the high genetic heterogeneity of autism, sequencing whole exomes from a large number of individuals with autism will be more a practical way to identify autism genes, including both novel and previously reported ones. A 2011 study reported the first whole-exome sequencing study in individuals with autism and identified several ”de novo” mutations5 associated with the disorder.