Cascade health service use in family members following genetic testing in children: a scoping literature review

Experience with cascade screening: A comprehensive family pedigree analysis of two index patients with Fabry disease

The wide range of clinical symptoms observed in patients with Fabry disease (FD) often leads to delays in diagnosis and initiation of treatment. Delayed initiation of therapy may result in end-organ damage, such as chronic renal failure, hypertrophic cardiomyopathy, and stroke. Although some tools are available to identify undiagnosed patients, new comprehensive screening methods are needed. In this study, the outcomes of the cascade screening applied to three index cases with FD from 2 familes were investigated. In the pedigree analysis, 280 individuals were included; out of them, 131 individuals underwent genetic testing and cascade screening for FD. During the screening program, a total of 45 individuals were diagnosed, with a diagnostic ratio of 1:15. The average age at diagnosis for all individuals was 30.9 ± 17.7 years, and %25 were pediatric cases (mean age 9.5 ± 5.9 years). Thirty affected relatives were diagnosed from the two index cases in Family 1 and 15 individuals were diagnosed from one index case in Family 2. There were 13 consanguineous marriages observed among 2 pedigres, in two both spouses  were affected, leading to two homozygous affected daughters in one couple. In regions where there is a high prevalence of consanguineous marriages, implementing the cascade screening approach to identify all individuals at risk can be beneficial for patients with FD, specifically women and children.

Protocol for a Prospective, Observational Cost-effectiveness Analysis of Returning Secondary Findings of Genome Sequencing for Unexplained Suspected Genetic Conditions

PURPOSE

Although costly, genome-wide sequencing (GWS) detects an extensive range of variants, enhancing our ability to diagnose and assess risk for an increasing number of diseases. In addition to detecting variants related to the indication for testing, GWS can detect secondary variants in BRCA1, BRCA2, and other genes for which early intervention may improve health. As the list of secondary findings grows, there is increased demand for surveillance and management by multiple specialists, adding pressure to constrained health care budgets. Secondary finding testing is actively debated because some consider it opportunistic screening for future health risks that may not manifest. Given the economic implications of secondary finding testing and follow-up and its unproven clinical utility, the objective is to assess the incremental cost-effectiveness of secondary finding ascertainment per case detected and per unit of improved clinical utility in families of children with unexplained suspected genetic conditions undergoing clinical GWS.

METHODS

Those undergoing trio genome or exome sequencing are eligible for the study. Positive secondary finding index cases will be matched to negative controls (1:2) based on age group, primary result(s) type, and clinical indication. During the 2-year study, 71 cases and 142 matched controls are expected. Health service use will be collected in patients and 1 adult family member every 6 months. The per-child and per-dyad total cost will be determined by multiplying use of each resource by a corresponding unit price and summing all cost items. Costs will be estimated from the public and societal payer perspectives. The mean cost per child and per dyad for secondary finding-positive and secondary finding-negative groups will be compared statistically. If important demographic differences are observed between groups, ordinary least-squares regression, log transformation, or other nonparametric technique will be used to compare adjusted mean costs. The ratio of the difference in mean cost to the secondary finding yield will be used to estimate incremental cost-effectiveness. In secondary analyses, effectiveness will be estimated using the number of clinical management changes due to secondary findings or the Clinician-Reported Genetic Testing Utility Index (C-GUIDE) score, a validated measure of clinical utility. Sensitivity analysis will be undertaken to assess the robustness of the findings to variation in key parameters.

IMPLICATIONS

This study generates key evidence to inform clinical practice and funding allocation related to secondary finding testing. The inclusion of family members and a new measure of clinical utility represent important advancements in economic evaluation in genomics.

Cascade testing after exome sequencing: Retrospective analysis of linked family data at 2 US laboratories

PURPOSE

Cascade testing, the process of testing a proband's at-risk relatives, is integral to realizing the full value of genomic sequencing. However, there is little empirical evidence on the uptake of cascade testing after a positive exome sequencing (ES) result in a population of probands with diverse clinical indications.

METHODS

We retrospectively reviewed administrative data from 2 US clinical laboratories that perform ES. For each proband with a positive ES result, we used linked family data to describe the frequency of relatives' cascade testing performed at the same laboratory, variant detection yield of cascade tests, and characteristics of probands and relatives categorized on the basis of cascade testing completion.

RESULTS

Among the 3723 positive ES results across both laboratories, 426 relatives of 282 probands completed cascade testing (uptake = 7.6%). An average of 1.5 relatives (SD = 0.9) were tested per proband. Of the 426 relatives tested, 200 had a variant of interest detected (variant detection yield = 47.0%).

CONCLUSION

In our real-world data analysis, a small proportion of probands with a positive ES result subsequently had relatives complete cascade testing at the same laboratory. However, approximately half of the tested relatives received a clinically significant result that could have implications for clinical management or reproductive planning. Additional research on ways to increase cascade testing uptake is warranted.

2022 Association of Professors of Human and Medical Genetics (APHMG) consensus-based update of the core competencies for undergraduate medical education in genetics and genomics

PURPOSE

The field of genetics and genomics continues to expand at an unprecedented pace. As scientific knowledge is translated to clinical practice, genomic information is routinely being used in preventive, diagnostic, and therapeutic decision-making across a variety of clinical practice areas. As adoption of genomic medicine further evolves, health professionals will be required to stay abreast of new genetic discoveries and technologies and implementation of these advances within their scope of practice will be indicated.

METHODS

The Association of Professors of Human and Medical Genetics previously developed medical school genetics core competencies, last updated in 2013. The competencies were reviewed and updated through a structured approach incorporating a modified Delphi method.

RESULTS

The updated Association of Professors of Human and Medical Genetics core competencies are presented. Current revisions include competencies that are concise, specific, and assessable. In addition, they incorporate recent advances in clinical practice and promote equity and inclusion in clinical care.

CONCLUSION

The 2022 competencies will serve as a guide for medical school leadership and educators involved in curriculum development, implementation, and assessment. Use of these competencies across the undergraduate medical curricula will foster knowledge, skills, and behaviors required in medical practice across a wide range of specialties.

The Impact of Proband Indication for Genetic Testing on the Uptake of Cascade Testing Among Relatives

Although multiple factors can influence the uptake of cascade genetic testing, the impact of proband indication has not been studied. We performed a retrospective, cross-sectional study comparing cascade genetic testing rates among relatives of probands who received either diagnostic germline testing or non-indication-based proactive screening via next-generation sequencing (NGS)-based multigene panels for hereditary cancer syndromes (HCS) and/or familial hypercholesterolemia (FH). The proportion of probands with a medically actionable (positive) finding were calculated based on genes associated with Centers for Disease Control and Prevention (CDC) Tier 1 conditions, HCS genes, and FH genes. Among probands with a positive finding, cascade testing rates and influencing factors were assessed. A total of 270,715 probands were eligible for inclusion in the study (diagnostic n = 254,281,93.9%; proactive n = 16,434, 6.1%). A positive result in a gene associated with a CDC Tier 1 condition was identified in 10,520 diagnostic probands (4.1%) and 337 proactive probands (2.1%), leading to cascade testing among families of 3,305 diagnostic probands (31.4%) and 36 proactive probands (10.7%) (p < 0.0001). A positive result in an HCS gene was returned to 23,272 diagnostic probands (9.4%) and 970 proactive probands (6.1%), leading to cascade testing among families of 6,611 diagnostic probands (28.4%) and 89 proactive probands (9.2%) (p < 0.0001). Cascade testing due to a positive result in an HCS gene was more commonly pursued when the diagnostic proband was White, had a finding in a gene associated with a CDC Tier 1 condition, or had a personal history of cancer, or when the proactive proband was female. A positive result in an FH gene was returned to 1,647 diagnostic probands (25.3%) and 67 proactive probands (0.62%), leading to cascade testing among families of 360 diagnostic probands (21.9%) and 4 proactive probands (6.0%) (p < 0.01). Consistently higher rates of cascade testing among families of diagnostic probands may be due to a perceived urgency because of personal or family history of disease. Due to the proven clinical benefit of cascade testing, further research on obstacles to systematic implementation and uptake of testing for relatives of any proband with a medically actionable variant is warranted.