Outcome of Whole Exome Sequencing for Diagnostic Odyssey Cases of an Individualized Medicine Clinic: The Mayo Clinic Experience.

OBJECTIVE: To describe the experience and outcome of performing whole-exome sequencing (WES) for resolution of patients on a diagnostic odyssey in the first 18 months of an individualized medicine clinic (IMC). PATIENTS AND METHODS: The IMC offered WES to physicians of Mayo Clinic practice for patients with suspected genetic disease. DNA specimens of the proband and relatives were submitted to WES laboratories. We developed the Genomic Odyssey Board with multidisciplinary expertise to determine the appropriateness for IMC services, review WES reports, and make the final decision about whether the exome findings explain the disease. This study took place from September 30, 2012, to March 30, 2014. RESULTS: In the first 18 consecutive months, the IMC received 82 consultation requests for patients on a diagnostic odyssey. The Genomic Odyssey Board deferred 7 cases and approved 75 cases to proceed with WES. Seventy-one patients met with an IMC genomic counselor. Fifty-one patients submitted specimens for WES testing, and the results have been received for all. There were 15 cases in which a diagnosis was made on the basis of WES findings; thus, the positive diagnostic yield of this practice was 29%. The mean cost per patient for this service was approximately $8000. Medicaid supported 27% of the patients, and 38% of patients received complete or partial insurance coverage. CONCLUSION: The significant diagnostic yield, moderate cost, and notable health marketplace acceptance for WES compared with conventional genetic testing make the former method a rational diagnostic approach for patients on a diagnostic odyssey.

Whole-Exome Sequencing of 10 Scientists: Evaluation of the Process and Outcomes.

OBJECTIVE: To understand motivations, educational needs, and concerns of individuals contemplating whole-exome sequencing (WES) and determine what amount of genetic information might be obtained by sequencing a generally healthy cohort so as to more effectively counsel future patients. PATIENTS AND METHODS: From 2012 to 2014, 40 medically educated, generally healthy scientists at Mayo Clinic were invited to have WES conducted on a research basis; 26 agreed to be in a drawing from which 10 participants were selected. The study involved pre- and posttest genetic counseling and completion of 4 surveys related to the experience and outcomes. Whole-exome sequencing was conducted on DNA from blood from each person. RESULTS: Most variants (76,305 per person; range, 74,505-77,387) were known benign allelic variants, variants in genes of unknown function, or variants of uncertain significance in genes of known function. The results of suspected pathogenic/pathogenic variants in Mendelian disorders and pharmacogenomic variants were disclosed. The mean number of suspected pathogenic/pathogenic variants was 2.2 per person (range, 1-4). Four pharmacogenomic genes were included for reporting; variants were found in 9 of 10 participants. CONCLUSION: This study provides data that may be useful in establishing reality-based patient expectations, outlines specific points to cover during counseling, and increases confidence in the feasibility of providing adequate preparation and counseling for WES in generally healthy individuals.

Exome sequencing reveals frequent deleterious germline variants in cancer susceptibility genes in women with invasive breast cancer undergoing neoadjuvant chemotherapy.

When sequencing blood and tumor samples to identify targetable somatic variants for cancer therapy, clinically relevant germline variants may be uncovered. We evaluated the prevalence of deleterious germline variants in cancer susceptibility genes in women with breast cancer referred for neoadjuvant chemotherapy and returned clinically actionable results to patients. Exome sequencing was performed on blood samples from women with invasive breast cancer referred for neoadjuvant chemotherapy. Germline variants within 142 hereditary cancer susceptibility genes were filtered and reviewed for pathogenicity. Return of results was offered to patients with deleterious variants in actionable genes if they were not aware of their result through clinical testing. 124 patients were enrolled (median age 51) with the following subtypes: triple negative (n = 43, 34.7%), HER2+ (n = 37, 29.8%), luminal B (n = 31, 25%), and luminal A (n = 13, 10.5%). Twenty-eight deleterious variants were identified in 26/124 (21.0%) patients in the following genes: ATM (n = 3), BLM (n = 1), BRCA1 (n = 4), BRCA2 (n = 8), CHEK2 (n = 2), FANCA (n = 1), FANCI (n = 1), FANCL (n = 1), FANCM (n = 1), FH (n = 1), MLH3 (n = 1), MUTYH (n = 2), PALB2 (n = 1), and WRN (n = 1). 121/124 (97.6%) patients consented to return of research results. Thirteen (10.5%) had actionable variants, including four that were returned to patients and led to changes in medical management. Deleterious variants in cancer susceptibility genes are highly prevalent in patients with invasive breast cancer referred for neoadjuvant chemotherapy undergoing exome sequencing. Detection of these variants impacts medical management.

Implementing individualized medicine into the medical practice.

There is increasing recognition that genomic medicine as part of individualized medicine has a defined role in patient care. Rapid advances in technology and decreasing cost combine to bring genomic medicine closer to the clinical practice. There is also growing evidence that genomic-based medicine can advance patient outcomes, tailor therapy and decrease side effects. However the challenges to integrate genomics into the workflow involved in patient care remain vast, stalling assimilation of genomic medicine into mainstream medical practice. In this review we describe the approach taken by one institution to further individualize medicine by offering, executing and interpreting whole exome sequencing on a clinical basis through an enterprise-wide, standalone individualized medicine clinic. We present our experience designing and executing such an individualized medicine clinic, sharing lessons learned and describing early implementation outcomes.

Genetic testing utilization and the role of the laboratory genetic counselor.

Laboratory genetic counselors within hospital laboratories and genetic testing laboratories have an important role in increasing the appropriate utilization of genetic tests. This service is becoming more important as genetic testing becomes more complex and the demand for genetic testing in healthcare increases. Additionally genetic tests are among the most expensive assays in the clinical laboratory test catalog. Laboratory genetic counselors are able to increase genetic test utilization through review and assessment of the appropriateness of the ordered testing, developing protocols, and by increasing communication with ordering providers.