New approach successfully traces genomic variants back to genetic disorders

Jan. 6, 2023
NIH study shows genotype-first approach uncovers new links to genetic conditions.

National Institutes of Health researchers have published an assessment of 13 studies that took a genotype-first approach to patient care.

This approach contrasts with the typical phenotype-first approach to clinical research, which starts with clinical findings. A genotype-first approach to patient care involves selecting patients with specific genomic variants and then studying their traits and symptoms; this finding uncovered new relationships between genes and clinical conditions, broadened the traits and symptoms associated with known disorders, and offered insights into newly described disorders. The study was published in the American Journal of Human Genetics.

The study documents three types of discoveries from a genotype-first approach.

First, the researchers found that this approach helped discover new relationships between genomic variants and specific clinical traits. For example, one NIH study found that having more than two copies of the TPSAB1 gene was associated with symptoms related to the gastrointestinal tract, connective tissues, and the nervous system.

Second, this approach helped researchers find novel symptoms related to a disorder that clinicians previously missed because the patient did not have the typical symptoms. NHGRI researchers identified a person with a genomic variant associated with a known metabolic disorder. Further testing found that the individual had high levels of certain chemicals in their body associated with the disorder, despite having only minor symptoms.

Third, this approach allowed researchers to determine the function of specific genomic variants, which has the potential to help clinicians understand newly described disorders. For example, in one study, NHGRI researchers and their collaborators found that a genomic variant was associated with immune dysfunction at the molecular level in blood cells.

The 13 studies that implemented a genotype-first approach used genomic data from NHGRI’s Reverse Phenotyping Core in the Center for Precision Health Research. The core aggregates genomic data from programs such as ClinSeq(R) and the National Institute of Allergy and Infectious Disease (NIAID) Centralized Sequencing Protocol, which together allowed analyses to be performed on more than 16,000 research participants who have undergone genome or exome sequencing.

NIH release