Evaluation of the diagnostic accuracy of exome sequencing and its impact on diagnostic thinking for patients with rare disease in a publicly funded health care system: A prospective cohort study.

PURPOSE: To evaluate the diagnostic utility of publicly funded clinical exome sequencing (ES) for patients with suspected rare genetic diseases. METHODS: We prospectively enrolled 297 probands who met eligibility criteria and received ES across 5 sites in Ontario, Canada, and extracted data from medical records and clinician surveys. Using the Fryback and Thornbury Efficacy Framework, we assessed diagnostic accuracy by examining laboratory interpretation of results and assessed diagnostic thinking by examining the clinical interpretation of results and whether clinical-molecular diagnoses would have been achieved via alternative hypothetical molecular tests. RESULTS: Laboratories reported 105 molecular diagnoses and 165 uncertain results in known and novel genes. Of these, clinicians interpreted 102 of 105 (97%) molecular diagnoses and 6 of 165 (4%) uncertain results as clinical-molecular diagnoses. The 108 clinical-molecular diagnoses were in 104 families (35% diagnostic yield). Each eligibility criteria resulted in diagnostic yields of 30% to 40%, and higher yields were achieved when >2 eligibility criteria were met (up to 45%). Hypothetical tests would have identified 61% of clinical-molecular diagnoses. CONCLUSION: We demonstrate robustness in eligibility criteria and high clinical validity of laboratory results from ES testing. The importance of ES was highlighted by the potential 40% of patients that would have gone undiagnosed without this test.

Knowledge, perceptions, attitudes, and barriers pertaining to genetic literacy among surgeons: a scoping review.

BACKGROUND: The rapid evolution of genetic technologies and utilization of genetic information for clinical decision-making has necessitated increased surgeon participation in genetic counselling, testing, and appropriate referral of patients for genetic services, without formal training in genetics. We performed a scoping review to describe surgeons' knowledge, perceptions, attitudes, and barriers pertaining to genetic literacy in the management of patients who had confirmed cancer or who were potentially genetically at risk. METHODS: We conducted a scoping review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews checklist. We performed a comprehensive literature search, and 2 reviewers independently screened studies for inclusion. These studies included surgeons involved in the care of patients with confirmed gastrointestinal, breast, and endocrine and neuroendocrine cancers, or patients who were potentially genetically at risk for these cancers. RESULTS: We analyzed 17 studies, all of which used survey or interview-based formats. Many surgeons engaged in genetic counselling, testing, and referral, but reported low confidence and comfort in doing so. Knowledge assessments showed lower confidence in identifying genetic inheritance patterns and hereditary cancer syndromes, but awareness was higher among surgeons with greater clinical volume or subspecialty training in oncology. Surgeons felt responsible for facilitating these services and explicitly requested educational support in genetics. Barriers to genetic literacy were identified and catalogued at patient, surgeon, and system levels. CONCLUSION: Surgeons frequently engage in genetics-related tasks despite a lack of formal genetics training, and often report low knowledge, comfort, and confidence in providing such services. We have identified several barriers to genetic literacy that can be used to develop interventions to enhance genetic literacy among surgeons.

Feasibility Study and Clinical Impact of Incorporating Breast Tissue Density in High-Risk Breast Cancer Screening Assessment.

Breast tissue density (BTD) is known to increase the risk of breast cancer but is not routinely used in the risk assessment of the population-based High-Risk Ontario Breast Screening Program (HROBSP). This prospective, IRB-approved study assessed the feasibility and impact of incorporating breast tissue density (BTD) into the risk assessment of women referred to HROBSP who were not genetic mutation carriers. All consecutive women aged 40-69 years who met criteria for HROBSP assessment and referred to Genetics from 1 December 2020 to 31 July 2021 had their lifetime risk calculated with and without BTD using Tyrer-Cuzick model version 8 (IBISv8) to gauge overall impact. McNemar's test was performed to compare eligibility with and without density. 140 women were referred, and 1 was excluded (BRCA gene mutation carrier and automatically eligible). Eight of 139 (5.8%) never had a mammogram, while 17/131 (13%) did not have BTD reported on their mammogram and required radiologist review. Of 131 patients, 22 (16.8%) were clinically impacted by incorporation of BTD: 9/131 (6.9%) became eligible for HROBSP, while 13/131 (9.9%) became ineligible (p = 0.394). It was feasible for the Genetics clinic to incorporate BTD for better risk stratification of eligible women. This did not significantly impact the number of eligible women while optimizing the use of high-risk supplemental MRI screening.

Increased nuchal translucency thickness: a potential indicator for Ritscher-Schinzel syndrome.

OBJECTIVE: The Ritscher-Schinzel syndrome (RSS), also known as the 3C syndrome, is an autosomal recessive disorder classically comprising craniofacial, cerebellar and cardiac defects. The underlying molecular etiology remains unknown; therefore, prenatal diagnosis of recurrences depends on identification of the associated structural anomalies on second trimester ultrasound examination. Identification of recurrences using first-trimester ultrasound has not been reported previously. METHODS: Two women who presented at our center with fetal nuchal abnormalities on first trimester ultrasound went on to have children with RSS. One of the women had also undergone a previous pregnancy termination for fetal anomalies consistent with RSS. The ultrasound findings and details of these 3 cases were reviewed. RESULTS: Both cases of RSS and the third suspected case were found to have nuchal abnormalities on first-trimester scan. All went on to develop malformations consistent with RSS detectable on second-trimester ultrasound. The later 2 cases continued to term and the children had facial characteristics consistent with RSS. CONCLUSION: First-trimester ultrasound assessment of nuchal translucency could be considered as a method for identifying sib recurrences of RSS. In addition, RSS should be on the differential diagnosis when increased nuchal translucency is seen on first-trimester scan.