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Cancer Susceptibility (including unclassified variants)

Genetic variant databases

Link directly to databases >>>

When testing a gene, many different types of genetic changes are identified. Some genetic changes clearly impair the function of the gene (that is, they are pathogenic) and may cause disease. Other genetic changes are benign – causing no problems with the gene and creating no medical problems for the individual. 

However, some genetic changes are not easily classified as either pathogenic or benign. These genetic changes are called unclassified variants. Unclassified variants present a dilemma for researchers, clinicians, and patients – all of whom are seeking clear, informative genetic test results. When an unclassified variant is identified in a patient’s genetic test results, it is unknown whether or not that variant has caused or could cause disease in the patient (or his/her family members). 

Many researchers are working to gain more information about variants to definitively classify them as benign or pathogenic. However, this research takes time. Until a variant can be classified, care for patients and their relatives is typically planned using what is definitely known – with tailored treatment and screening recommendations based on the patient’s personal and family history rather than the genetic variant.

Researchers at Huntsman Cancer Institute at the University of Utah (HCI) have been involved with unclassified variant research for many years. Their research has focused on classifying variants in genes associated with hereditary cancer risk, including BRCA1 and BRCA2 and the mismatch repair genes. To increase access to genetic variant information, we have created this portal. By following the links below, you can access multiple internal and external databases full of information on variants in genes associated with hereditary cancer. You can also review Powerpoint slides, videos, and articles on the topic of genetic variants. These databases are updated frequently, so we encourage you to check back regularly. 

If you have questions on genetic variant research, please contact

If you or one of your patients has received a genetic test result containing an unclassified variant and you are looking for additional clinical guidance, please contact the Family Cancer Assessment Clinic at HCI at 801-587-9555. One of the genetic counselors can assist you.

Huntsman Cancer Institute and University of Utah managed sites

Resource Genes Resource Description
HCI BRCA1/2 Classified Variant Database BRCA1/2 Curated published data on variants
HCI BRCA1/2 Prior Probabilities Database BRCA1/2 Data on all possible single nucleotide substitutions in BRCA1/2
HCI MMR: Prior Probabilities and Classified Variants Database Mismatch repair (MLH1, MSH2, PMS2, MSH6) Data on all possible single nucleotide substitutions in the MMR genes

External managed sites

Resource Genes Resource Description
LOVD-For paraganglioma genes (FH, SDHX) LOVD-For Paraganglioma genes (FH, SDHX) Curated published data on variants
IARC TP53 TP53 Curated published data on germline and tumor variants
InSIGHT Mismatch Repair/APC/CDH1 Curated published data on germline variants
Breast Cancer Information Core BRCA1/2 Database of submitted VUS information from researchers and clinicians, classifications if available
Evidence-Based Network for the Interpretation of Germline Alleles (ENIGMA) Multiple Submit variants for research


Clinical resources at Huntsman Cancer Institute

Family Cancer Assessment Clinic (FCAC) - providing clinical genetics evaluations and hereditary cancer risk assessment for patients

Research resources at Huntsman Cancer Institute

Cancer Genetics Study (CGS) - enrolling patients with personal or family histories that suggest increased cancer risk to gain and refine knowledge about hereditary cancer