Organic Acidemia Genetic Testing 101

Types of Genetic Testing

Single Gene Sequencing: Single gene sequencing looks for changes, called variants or mutations, in one specific gene. This is typically the most affordable option because it requires fewer materials and less analysis. A clinician may order this type of test to confirm a diagnosis that was already suggested by lab results or other testing. The main limitation is that if no mutation is found in that one gene, additional testing will be needed to look at other genes that could be responsible for the condition.

Gene Panel: A gene panel simultaneously tests a group of genes known to cause similar diseases. For example, organic acidemia panels exist that test for mutations in genes associated with propionic acidemia, methylmalonic acidemia, glutaric acidemia, and others. These panels can include anywhere from a few dozen to several hundred genes, making them a useful option when the specific diagnosis is not yet clear.

Whole Exome Sequencing: The exome is the portion of your DNA that contains the direct instructions for making proteins. Whole exome sequencing looks for mutations across your entire exome all at once, making it a broad and thorough search. This type of testing has become increasingly common and is sometimes covered by insurance, though coverage varies. It is often considered when panel testing has not provided a clear answer.

Whole Genome Sequencing: Your genome is the complete set of all your DNA. This includes the exome as well as non-coding regions of DNA that do not carry direct instructions for making proteins. Researchers have discovered that variants in non-coding regions can cause disease, though this is not common in organic acidemias. Whole genome sequencing is the most comprehensive type of testing available, but it is also the most complex to interpret and is typically reserved for cases where other testing has not led to a diagnosis.