Editor's Note: This post has been updated to clarify the shortcomings of exome sequencing. HT: Robert West
At the Scientific American Guest Blog, author and genetic counselor Ricki Lewis says that while exome sequencing is a "powerful" tool, there are 10 things it doesn't do very well. "Analyzing an exome to understand a disease is, in some cases, like reading the CliffsNotes version of a classic book," Lewis says. Exome sequencing won't detect all exons; mutations in mitochondrial genes; structural variants, like translocations or inversions; triple repeat disorders like Huntington's disease; certain copy-number variants; introns; uniparental disomy; control sequences; epistatic interactions; or epigenetic changes, she says.
However, Lewis adds, there are three cases when exome sequencing is definitely the tool to use — finding a mutation in a known gene, finding mutations in novel genes, and discovery of mutations that should cause a particular trait or illness in a person, but where there was incomplete penetrance and the person was spared the illness.